Charging system and charging method for terminal and power adapter

ABSTRACT

A charging system, a charge method, and a power adapter are provided. The charging system includes a battery, a first rectifying circuit, a switch circuit, a transformer, a second rectifying circuit, a sampling circuit, and a control circuit. The control circuit outputs a control signal to the switch circuit, and regulates a duty cycle of the control signal according to the current sampling value so that the voltage with the third pulsating waveform satisfies a requirement of charging the battery.

BACKGROUND 1. Field of Disclosure

The present disclosure relates to a terminal device technology, moreparticularly, to a charging system for a terminal, a charging method forthe terminal, and a power adapter.

2. Description of Related Art

Currently, mobile terminals (such as a smart phone) are increasinglypopular with consumers. However, the mobile terminals consume a greatamount of power so that they need to be charged frequently.

The mobile terminals are usually charged through power adapters. A poweradapter generally includes a primary rectifier circuit, a primary filtercircuit, a transformer, a secondary rectifier circuit, a secondaryfilter circuit, and a control circuit, etc. The power adapter convertsinput 220V alternating current (AC) power into a stable low-voltagedirect current (DC) power (such as 5V) suitable for the mobile terminal,so as to provide power to a power management device and a battery of themobile terminal, thus charging the mobile terminal .

However, as the power of the power adapters increases, for example, whenthe power is upgraded from 5 W to a higher power, such as 10 W, 15 W, 25W etc., more electronic components that can sustain a higher power andrealize a higher control of accuracy are needed for complementing eachother. This causes size of the power adapters to increase as well asmanufacturing difficulty of the adapters to also increase.

In general, current flowing through the power adapter of related art isdetected with a current sensing resistor and an operational amplifier.The sensing current becomes greater as power of the power adapterbecomes greater. Correspondingly, under the premise that the operationalamplifier is not saturated, the dynamic range of the detective currentis more limited. However, when the mobile terminal is charged with smallcurrent outputted by the power adapter, a wider dynamic range of theoperational amplifier by using a smaller current sensing resistor orselecting a lower amplification of the operational amplifier) may resultin inaccuracy of detection of the small current because of thecharacteristic of the operational amplifier, which further affects theapplication of the power adapter.

SUMMARY

The present application is based on the inventor's knowledge andresearch on the following issues.

With the power of a power adapter becomes higher, the battery tends topolarize and the resistance tends to become larger when the poweradapter charges the battery of the mobile terminal; the batterytemperature thus rises to reduce the service life of the battery. As aresult, the reliability and safety of the battery are affected.

In addition, when an AC power supplies power, most of the equipmentcannot operate by directly using the AC power. The reason is that an ACpower, such as 220V/50 Hz mains, outputs power intermittently, and inorder not to be “intermittent”, electrolytic capacitors need to be usedfor energy storage. When the power is at the wave trough, the powersupply is maintained stably by continuously relying on the energystorage of electrolytic capacitors. Therefore, when a mobile terminal ischarged by an AC power supply through a power adapter, the AC power,such as 220V AC power, provided by the AC power supply is firstconverted into a stable DC power be supplied to the mobile terminal.However, the power adapter charges the battery of the mobile terminal,thus indirectly supplying power to the mobile terminal. The continuityof power supply can be ensured by the battery. As such, the poweradapter does not need to continuously output a stable DC power whencharging the battery.

Therefore, one objective of the present disclosure is to provide acharging system for a terminal. With the charging system, voltage with apulsating waveform outputted by a power adapter is directly applied to abattery of the terminal, thereby miniaturizing the power adapter,lowering the cost of the power adapter, and increasing the lifetime ofthe battery. Besides, two current sampling modes are alternativelyswitched to sample the current, which ensures the sensing function withthe compatibility between sensing precision and dynamic range andexpands the scope of the applications.

Another objective of the present disclosure is to provide a poweradapter. Still another objective of the present disclosure is to providea charging method for a terminal.

In order to achieve at least one of the above objectives, one aspect ofthe present disclosure provides a charging system for a terminal. Thecharging system for a terminal includes a power adapter. The poweradapter includes a first rectifying circuit configured to rectify analternating current to voltage with a first pulsating waveform, a switchcircuit configured to modulate the voltage with the first pulsatingwaveform according to a control signal, a transformer configured tooutput voltage with a second pulsating waveform according to themodulated voltage with the first pulsating waveform, a second rectifyingcircuit configured to rectify the voltage with the second pulsatingwaveform to voltage in a third pulsating waveform, a first charginginterface coupled to the second rectifying circuit, a first currentsampling circuit configured to sample current outputted by the secondrectifying circuit to obtain a current sampling value, the first currentsampling circuit selectively operable in a first current sampling modeand a second current sampling mode, a mode switch circuit configured tocontrol the first current sampling circuit to switch between the firstcurrent sampling mode and the second current sampling mode, and acontrol circuit coupled to the first current sampling circuit, the modeswitch circuit, and the mode switch circuit. The control circuit isconfigured to output the control signal to the switch circuit,configured to control the mode switch circuit to control the firstcurrent sampling circuit operating in the first current sampling mode orthe second current sampling mode based on a charging mode, andconfigured to regulate a duty cycle of the control signal according tothe current sampling value so that the voltage with the third pulsatingwaveform satisfies a requirement of charging. The terminal includes abattery and a second charging interface coupled to the battery, whereinthe voltage with the third pulsating waveform is applied to the batterywhen the second charging interface couples to the first charginginterface.

According to the embodiment of the present disclosure, the chargingsystem for the terminal controls the power adapter to output the voltagewith the third pulsating waveform, and directly applies the voltage withthe third pulsating waveform output from the power adapter to thebattery in the terminal, so that the fast charging of the batterydirectly by the output voltage/current that is pulsating can beachieved. A magnitude of the output voltage/current that is pulsatingchanges periodically. As compared with the disclosures of charging withconstant voltage and constant current in the related art, the lithiumprecipitation phenomenon of the lithium battery can be reduced. Theservice life of the battery can be improved. In addition, theprobability of arcing and the force of the contact at the charginginterface can further be reduced to improve the life of the charginginterface. It is also advantageous in reducing the polarization effectof the battery, improving the charging speed, reducing the battery heatso as to ensure the safety and reliability when the terminal is charged.Additionally, because the power adapter outputs the voltage with thepulsating waveform, there is no necessity to dispose electrolyticcapacitors in the power supply adapter. Not only can the power adapterbe simplified and miniaturized, but the cost can also be greatlyreduced. Additionally, two current sampling modes are alternativelyswitched to sample the current, which ensures the sensing function withthe compatibility between sensing precision and dynamic range andexpands the scope of the applications.

In order to achieve at least one of the above objectives, another aspectof the present disclosure provides a power adapter. The power adapterincludes a first rectifying circuit configured to rectify an alternatingcurrent to voltage with a first pulsating waveform, a switch circuitconfigured to modulate the voltage with the first pulsating waveformaccording to a control signal, a transformer configured to outputvoltage with a second pulsating waveform according to the modulatedvoltage with the first pulsating waveform, a second rectifying circuitconfigured to rectify the voltage with the second pulsating waveform tovoltage in a third pulsating waveform, a first charging interfacecoupled to the second rectifying circuit, a first current samplingcircuit configured to sample current outputted by the second rectifyingcircuit to obtain a current sampling value, the first current samplingcircuit selectively operable in a first current sampling mode and asecond current sampling mode, a mode switch circuit configured tocontrol the first current sampling circuit to switch between the firstcurrent sampling mode and the second current sampling mode, and acontrol circuit coupled to the first current sampling circuit, the modeswitch circuit, and the mode switch circuit. The control circuit isconfigured to output the control signal to the switch circuit,configured to control the mode switch circuit to control the firstcurrent sampling circuit operating in the first current sampling mode orthe second current sampling mode based on a charging mode, andconfigured to regulate a duty cycle of the control signal according tothe current sampling value so that the voltage with the third pulsatingwaveform satisfies a requirement of charging. The first charginginterface is configured to apply the voltage with the third pulsatingwaveform to a battery of a terminal through a second charging interfaceof the terminal when the second charging interface of the terminalcouples to the first charging interface. The battery is coupled to thesecond charging interface.

According to the embodiment of the present disclosure, the power adapteroutputs the voltage with the third pulsating waveform through the firstcharging interface, and directly applies the voltage with the thirdpulsating waveform output from the power adapter to the battery throughthe second charging interface in the terminal, so that the fast chargingof the battery directly by the output voltage/current that is pulsatingcan be achieved. A magnitude of the output voltage/current that ispulsating changes periodically. As compared with the disclosures ofcharging with constant voltage and constant current in the related art,the lithium precipitation phenomenon of the lithium battery can bereduced. The service life of the battery can be improved. In addition,the probability of arcing and the force of the contact at the charginginterface can further be reduced to improve the life of the charginginterface. It is also advantageous in reducing the polarization effectof the battery, improving the charging speed, reducing the battery heatso as to ensure the safety and reliability when the terminal is charged.Additionally, because the power adapter outputs the voltage with thepulsating waveform, there is no necessity to dispose electrolyticcapacitors in the power supply adapter. Not only can the power adaptersimplified and miniaturized, but the cost can also be greatly reduced.Additionally, two current sampling modes are alternatively switched tosample the current, which ensures the sensing function with thecompatibility between sensing precision and dynamic range and expandsthe scope of the applications.

In order to achieve at least one of the above objectives, still anotheraspect of the present disclosure provides a charging method for aterminal. The charging method for the terminal includes the followingacts. An alternating current is rectified to output voltage with a firstpulsating waveform when a first charging interface of a power adaptercouples a second charging interface of the terminal. The voltage withthe first pulsating waveform is modulated by controlling a mode switchcircuit. The modulated voltage with the first pulsating waveform isconverted into voltage with a second pulsating waveform by atransformer. The voltage with the second pulsating waveform is rectifiedto output voltage in a third pulsating waveform. The voltage with thethird pulsating waveform is applied to a battery of the terminal throughthe second charging interface. Current corresponding to the voltage withthe third pulsating waveform is sampled to obtain a current samplingvalue, where the first current sampling circuit is selectively operablein a first current sampling mode and a second current sampling mode. Thefirst current sampling circuit is controlled to operate in the firstcurrent sampling mode or the second current sampling mode according to acharging mode, and regulating a duty cycle of the control signalaccording to the current sampling value so that the voltage with thethird pulsating waveform satisfies a requirement of charging.

According to the charging method provided in the embodiment of thepresent disclosure, the voltage with the third pulsating waveform isoutputted by controlling the power adapter, and the voltage with thethird pulsating waveform output from the power adapter is directlyapplied to the battery of the terminal, so that the fast charging of thebattery directly by the output voltage/current that is pulsating can beachieved. A magnitude of the output voltage/current that is pulsatingchanges periodically. As compared with the disclosures of charging withconstant voltage and constant current in the related art, the lithiumprecipitation phenomenon of the lithium battery can be reduced. Theservice life of the battery can be improved. In addition, theprobability of arcing and the force of the contact at the charginginterface can further be reduced to improve the life of the charginginterface. It is also advantageous in reducing the polarization effectof the battery, improving the charging speed, reducing the battery heatso as to ensure the safety and reliability when the terminal is charged.Additionally, because the power adapter outputs the voltage with thepulsating waveform, there is no necessity to dispose electrolyticcapacitors in the power supply adapter. Not only can the power adaptersimplified and miniaturized, but the cost can also be greatly reduced.Additionally, two current sampling modes are alternatively switched tosample the current, which ensures the sensing function with thecompatibility between sensing precision and dynamic range and expandsthe scope of the applications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a block schematic diagram of a charging system for aterminal that adopts a flyback switching power supply according to oneembodiment of the present disclosure.

FIG. 1B illustrates a block schematic diagram of a charging system for aterminal that adopts a forward switching power supply according to oneembodiment of the present disclosure.

FIG. 1C illustrates a block schematic diagram of a charging system for aterminal that adopts a push pull switching power supply according to oneembodiment of the present disclosure.

FIG. 1D illustrates a block schematic diagram of a charging system for aterminal that adopts a half-bridge switching power supply according toone embodiment of the present disclosure.

FIG. 1E illustrates a block schematic diagram of a charging system for aterminal that adopts a full-bridge switching power supply according toone embodiment of the present disclosure.

FIG. 2A illustrates a block schematic diagram of a charging system for aterminal according to one embodiment of the present disclosure.

FIG. 2B illustrates a circuit diagram of a first current samplingcircuit according to another embodiment of the present disclosure.

FIG. 3 illustrates a waveform of a charging voltage output to a batteryfrom a power adapter according to one embodiment of the presentdisclosure.

FIG. 4 illustrates a waveform of a charging current output to a batteryfrom a power adapter according to one embodiment of the presentdisclosure.

FIG. 5 illustrates a waveform of a control signal output to a switchcircuit according to one embodiment of the present disclosure.

FIG. 6 illustrates a schematic diagram of a fast charging processaccording to one embodiment of the present disclosure.

FIG. 7A illustrates a block schematic diagram of a charging system for aterminal according to one embodiment of the present disclosure.

FIG. 7B illustrates a block schematic diagram of a power adapter havingan LC filter circuit according to one embodiment of the presentdisclosure.

FIG. 8 illustrates a block schematic diagram of a charging system for aterminal according to another embodiment of the present disclosure.

FIG. 9 illustrates a block schematic diagram of a charging system for aterminal according to still another embodiment of the presentdisclosure.

FIG. 10 illustrates a block schematic diagram of a charging system for aterminal according to yet another embodiment of the present disclosure.

FIG. 11 illustrates a block schematic diagram of a sampling circuitaccording to one embodiment of the present disclosure.

FIG. 12 illustrates a block schematic diagram of a charging system for aterminal according to an additional embodiment of the presentdisclosure.

FIG. 13 illustrates a block schematic diagram of a terminal according toone embodiment of the present disclosure.

FIG. 14 illustrates a block schematic diagram of a terminal according toanother embodiment of the present disclosure.

FIG. 15 illustrates a flowchart of a charging method for a terminalaccording to one embodiment of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present application are illustrated in detail in theaccompanying drawings, in which like or similar reference numerals referto like or similar elements or elements having the same or similarfunctions throughout the specification. The embodiments described belowwith reference to the accompanying drawings are exemplary and areintended to be illustrative of the present application, and are not tobe construed as limiting the scope of the present application.

Before a charging system and a charging method for a terminal and apower adapter according to the embodiments of the present disclosure areprovided, description of a power adapter for charging a chargeabledevice (e.g. a terminal), that is, an “associated adapter” as called inthe following, in the relevant technology is first described.

The associated adapter constantly maintains an output voltage when theassociated adapter operates in a constant voltage mode, such as 5V, 9V,12V, or 20V, etc.

Voltage output from the associated adapter is not suitable to bedirectly applied to two terminals of a battery, rather, the voltageoutput from the associated adapter needs to be first converted through aconverter circuit in a chargeable device (such as a terminal) so as toobtain an expected charging voltage and/or a charging current by abattery in the chargeable device (such as a terminal).

The converter circuit is configured to convert the voltage output fromthe associated adapter so as to satisfy the expected requirement of thecharging voltage and/or the charging current by the battery.

As an example, the converter circuit may refer to a charging managementmodule, such as a charging IC in the terminal, which is configured tomanage the charging voltage and/or the charging circuit of the batteryduring the charging process of the battery. The converter circuit has afunction of a voltage feedback module and/or a function of a currentfeedback module to manage the charging voltage and/or the chargingcircuit of the battery.

For example, the charging process of the battery may include at leastone of a trickle charging stage, a constant current charging stage, anda constant voltage charging stage. During the trickle charging stage,the converter circuit can utilize a current feedback loop so that acurrent entering into the battery satisfies a magnitude of the chargingcurrent expected by the battery (such as a first charging current) inthe trickle charging stage. During the constant current charging stage,the converter circuit can utilize the current feedback loop so that thecurrent entering into the battery satisfies magnitude of the chargingcurrent expected by the battery (such as a second charging current, thesecond charging current may be greater than the first charging current)in the constant current charging stage. During the constant voltagecharging stage, the converter circuit can utilize a voltage feedbackloop so that voltage applied to the two terminals of the batterysatisfies a magnitude of the charging voltage expected by the battery inthe constant voltage charging stage.

As an example, when the voltage output from the associated adapter isgreater than the charging voltage expected by the battery, the convertercircuit can be configured to step down the voltage output from theassociated adapter so that the charging voltage obtained after buckconversion satisfies the charging voltage expected by the battery. Asanother example, when the voltage output from the associated adapter isless than the charging voltage expected by the battery, the convertercircuit can be configured to boost the voltage output from theassociated adapter so that the charging voltage obtained after the boostconversion satisfies the charging voltage expected by the battery.

In yet another example, a constant 5V voltage output from the associatedadapter is taken as an example. When the battery includes a single cell(take a lithium battery cell for example, a charging cut-off voltage ofa single cell is 4.2V), the converter circuit (such as a buck circuit)can step down the voltage output from the associated adapter so that thecharging voltage obtained after bucking satisfies the charging voltageexpected by the battery.

In yet another example, the constant voltage of 5V output from theassociated adapter is taken as an example. When the battery is a batteryhaving two or more than two single cells (take the lithium battery cellfor example, the charging cut-off voltage of the single cell is 4.2V)connected in series, the converter circuit (such as a boost circuit) canboost the voltage output from the associated adapter so that thecharging voltage obtained after boosting satisfies the charging voltageexpected by the battery.

Because the converter circuit is limited by low conversion efficiency ofthe circuit, electrical energy that is not converted, is dissipated in aform of heat. This heat will accumulate inside the chargeable device(such as the terminal), where a design space and a heat dissipationspace of the chargeable device (such as the terminal) are both limited(for example, a physical size of a mobile terminal used by a userbecomes increasingly thin and light, and a great number of electroniccomponents are closely arranged inside the mobile terminal to enhanceperformance of the mobile terminal). Not only does it create increaseddifficulty of designing the converter circuit, but also it is verydifficult to dissipate heat accumulated inside the chargeable device(such as the terminal) in a timely manner, thus causing the chargeabledevice (such as the terminal) to become abnormal.

For example, heat accumulated by the converter circuit is likely tocause thermal interference with electronic components near the convertercircuit so that the electronic components work abnormally; and/or, forexample, the heat accumulated on the converter circuit is likely toshorten service lives of the converter circuit and the electroniccomponents nearby; and/or, for example, the heat accumulated on theconverter circuit is likely to cause thermal interference with thebattery so that the battery charges and discharges abnormally; and/or,for example, the heat accumulated on the converter circuit is likely toraise temperature of the chargeable device (such as the terminal) sothat the user experience is affected when the user charges; and/or, forexample, the heat accumulated on the converter circuit is likely tocause a short circuit of the converter circuit itself so that thebattery charges abnormally when the voltage output from the associatedadapter is directly applied to the two terminals of a battery. Under thecircumstances that the battery is over charged for a long time, thebattery can even explode, which in turn causes a certain securityconcern.

A power adapter according to the embodiment of the present disclosurecan acquire battery state information. The battery state information atleast includes a current battery level information and/or voltageinformation. The power adapter adjusts an output voltage of the poweradapter itself based on the acquired battery state information tosatisfy a charging voltage and/or a charging current expected by thebattery. Voltage outputted by the power adapter after adjustment can bedirectly applied to two terminals of the battery to charge the battery.In some embodiments, an output of the power adapter may be voltage witha pulsating waveform.

The power adapter has functions of a voltage feedback module and acurrent feedback module, to achieve the management of the chargingvoltage and/or the charging circuit of the battery.

The power adapter adjusting the output voltage of the power adapteritself based on the acquired battery state information may refer to thepower adapter can acquire the battery state information in a real-timemanner and adjust the voltage output from the power adapter itself basedon real-time state information of the battery acquired every time, tosatisfy the charging voltage and/or the charging current expected by thebattery.

The power adapter adjusting the output voltage of the power adapteritself based on the battery state information acquired in a real-timemanner may refer to the power adapter can acquire current stateinformation of the battery at different times during a charging processas the charging voltage of the battery continues to rise during thecharging process, and adjust the output voltage of the power adapteritself based on the current state information of the battery in areal-time manner to satisfy the charging voltage and/or the chargingcurrent expected by the battery. The voltage output from the poweradapter after adjustment can be directly applied to the two terminals ofthe battery to charge the battery.

For example, the charging process of the battery may include at leastone of a trickle charging stage, a constant current charging stage, anda constant voltage charging stage. During the trickle charging stage,the power adapter can output a first charging current to charge thebattery so as to satisfy the charging current expected by the battery(in some embodiments, the first charging current may be current with apulsating waveform). During the constant current charging stage, thepower adapter can utilize a current feedback loop so that a currentoutput from the power adapter and enters into the battery satisfies thecharging current expected by the battery (for example, a second chargingcurrent, the second charging current may similarly be a current with apulsating waveform, the second charging current may be greater than thefirst charging current, a peak value of the current with the pulsatingwaveform of the constant current charging stage may be greater than apeak value of the current with the pulsating waveform of the tricklecharging stage, and a constant current of the constant current chargingstage may refer to the peak value or an average value of the currentwith the pulsating waveform basically remaining unchanged). During theconstant voltage charging stage, the power adapter can utilize a voltagefeedback loop so that voltage (that is, the voltage with the pulsatingwaveform) outputted from the power adapter to a piece of chargeabledevice (such as a terminal) in the constant voltage charging stage ismaintained constantly.

For example, the power adapter according to the embodiment of thepresent disclosure can be mainly configured to control the constantcurrent charging stage of the battery in the chargeable device (such asthe terminal). In other embodiments, functions of controlling thetrickle charging stage and the constant voltage charging stage of thebattery in the chargeable device (such as the terminal) may becooperatively achieved by the power adapter according to the embodimentof the present disclosure and an additional charging chip in thechargeable device (such as the terminal). When compared with theconstant current charging stage, charging power received by the batteryin the trickle charging stage and the constant voltage charging stage isless, the efficiency conversion loss and heat accumulation of thecharging chip in the chargeable device (such as the terminal) are thusacceptable. It is noted that the constant current charging stage or theconstant current stage according to the embodiment of the presentdisclosure may refer to the charging mode that controls an outputcurrent of the associated adapter and does not require that the outputcurrent of the power adapter to be maintained completely unchanged, forexample, may refer to that the peak value or the average value of thecurrent with the pulsating waveform output from the associated adapterbasically remains unchanged or basically remains unchanged within aperiod of time. For example, in practice, the power adapter in theconstant current charging stage usually uses a multi-stage constantcurrent charging method to charge.

The multi-stage constant current charging may have N constant currentstages (N is a positive integer not less than 2). The multi-stageconstant current charging uses a predetermined charging current to starta first charging stage. The N constant current stages of the multi-stageconstant current charging are sequentially executed from the first stageto the (N−1)th stage. After a previous constant current stage is changedto a next constant current stage in the constant current stages, thepeak value or the average value of the current with the pulsatingwaveform can become smaller. When a battery voltage reaches a thresholdvoltage value for terminating charging, the previous constant currentstage will change to the next constant current stage in the constantcurrent stages. The current conversion process between two adjacentconstant current stages may be gradual, or may be a stepped jump.

In addition, it is noted that the term “terminal” as used in theembodiments of the present disclosure may include, but is not limitedto, a device configured to be connected via a wired connection (forexample, via a public switched telephone network (PSTN), a digitalsubscriber line (DSL), a digital cable, a direct cable connection,and/or another data connection/network) and/or a device configured toreceive/send a communication signal via a wireless interface (such as acellular network, a wireless local area network (WLAN), a digitaltelevision network such as a DVB-H network, a satellite network, anAM-FM broadcast transmitter, and/or another communication terminal). Aterminal configured to communicate via a wireless interface may bereferred to as a “wireless communication terminal”, a “wirelessterminal”, and/or a “mobile terminal”. Examples of mobile terminalinclude, but are not limited to, a satellite or cell phone; a personalcommunication system (PCS) terminal that can combine a cellularradiotelephone, data processing, facsimile, and data communicationscapabilities; may include a radiotelephone, a pager, anInternet/Intranet access, a Web browser, an electronic organizer, acalendar, and/or a personal digital assistant (PDA) equipped with aglobal positioning System (GPS) receiver; and a common laptop and/orpalm type receiver or some other electronic devices including atransmitter-receiver radiotelephone.

In addition, according to the embodiment of the present disclosure, whenthe voltage with the pulsating waveform output from the power adapter isdirectly applied to the battery of the terminal so as to charge thebattery, the charging current is characterized by a pulsating wave, suchas a clipped sine wave, and it is understood that the charging currentcharges the battery in an intermittent manner. A period of the chargingcurrent changes depending on an input AC power, such as a frequency ofan AC grid. For example, a frequency corresponding to the period of thecharging current is an integer multiple or a reciprocal of the frequencyof the AC grid. Additionally, the charging current charges the batteryin an intermittent manner. A current waveform corresponding to thecharging current may be composed of one pulse or one group of pulsessynchronized with the grid.

A description of a charging system for a terminal and a power adapterand a charging method for a terminal according to the embodiment of thepresent disclosure is provided as follows with reference to the figures.

A description is provided with reference to FIG. 1A to FIG. 14. Acharging system for a terminal according to the embodiment of thepresent disclosure includes a power adapter 1 and a terminal 2.

As shown in FIG. 2A and FIG. 2B, the power adapter 1 includes a firstrectifying circuit 101, a switch circuit 102, a transformer 103, asecond rectifying circuit 104, a first charging interface 105, a firstcurrent sampling circuit 1061, a mode switch circuit 115 and a controlcircuit 107. The first rectifying circuit 101 rectifies an input ACpower (mains, such as AC220V) to output voltage in a first pulsationwaveform, such as a voltage in a clipped pulsating waveform. As shown inFIG. 1A, the first rectifying circuit 101 may be a full bridge rectifiercircuit constituted by four diodes. The switch circuit 102 is configuredto modulate the voltage with the first pulsating waveform based on acontrol signal. The switch circuit 102 may be constituted by ametal-oxide-semiconductor (MOS) transistor, and perform a peak clippingmodulation to the voltage in the clipped pulsating waveform throughperforming a pulse width modulation (PWM) control to the transistor. Thetransformer 103 is configured to output voltage with a second pulsatingform based on the voltage with the first pulsating form thus modulated.The second rectifying circuit 104 is configured to rectify the voltagewith the second pulsating waveform to output voltage in a thirdpulsating form. The second rectifying circuit 104 may be constituted bya diode or a MOS transistor, which can achieve secondary synchronousrectification so that the third pulsating waveform is synchronized withthe modulated first pulsating waveform. It is noted that the thirdpulsating waveform being synchronized with the modulated first pulsatingwaveform refers to that a phase of the third pulsating waveform and aphase of the modulated first pulsating waveform are consistent, and achange trend of an amplitude of the third pulsating waveform and achange trend of an amplitude of the modulated first pulsating waveformare consistent. The first charging interface 105 and the secondrectifying circuit 104 are connected. The first current sampling circuit1061 is configured to sample current outputted by the second rectifyingcircuit 104 to obtain a current sampling value. The first currentsampling circuit 1061 is selectively operable in a first currentsampling mode and a second current sampling mode. The mode switchcircuit 115 is configured to control the first current sampling circuit1061 to switch between the first current sampling mode and the secondcurrent sampling mode. The control circuit 107 is coupled to the firstcurrent sampling circuit 1061, the mode switch circuit 115, and theswitch circuit 102. The control circuit 107 is configured to output thecontrol signal to the switch circuit 102 to control the mode switchcircuit 115 to control the first current sampling circuit 1061 operatingin the first current sampling mode or the second current sampling modebased on a charging mode, and configured to regulate a duty cycle of thecontrol signal according to the current sampling value so that thevoltage with the third pulsating waveform satisfies a requirement ofcharging.

As shown in FIG. 2A, the terminal 2 includes a second charging interface201 and a battery 202. The second charging interface 201 is connected tothe battery 202. When the second charging interface 201 and the firstcharging interface 105 are connected, the second charging interface 201applies the voltage with the third pulsating waveform to the battery 202to achieve to charging of the battery 202.

In one embodiment of the present disclosure, as shown in FIG. 1A, thepower adapter 1 may adopt a flyback switching power supply. In greaterdetail, the transformer 103 includes a primary winding and a secondarywinding. One terminal of the primary winding is connected to a firstoutput terminal of the first rectifying circuit 101. A second outputterminal of the first rectifying circuit 101 is grounded. Anotherterminal of the primary winding is connected to the switch circuit 102(for example, the switch circuit 102 is the MOS transistor, so theanother terminal of the primary winding is connected to a drain of theMOS transistor). The transformer 103 is configured to output the voltagewith the second pulsating waveform based on the modulated voltage withthe first pulsating waveform.

The transformer 103 is a high-frequency transformer, which may have anoperating frequency of 50 KHz to 2 MHz. The modulated voltage with thefirst pulsating waveform is coupled to a secondary side by thehigh-frequency transformer and is output by the secondary winding.According to the embodiment of the present disclosure, using thehigh-frequency transformer can take advantage of the feature of smallersize of the high-frequency transformer as compared with a low-frequencytransformer (a low-frequency transformer is also called a powerfrequency transformer, which is mainly used for the mains frequency,such as 50 Hz or 60 Hz AC)), thus achieving the miniaturization of thepower adapter 1.

According to one embodiment of the present disclosure, as shown in FIG.1B, the power adapter 1 may adopt a forward switching power supply. Ingreater detail, the transformer 103 includes a first winding, a secondwinding, and a third winding. A dotted terminal of the first winding isconnected to a second output terminal of the first rectifying circuit101 through a backward diode. A non-dotted terminal of the first windingis first connected to a dotted terminal of the second winding and thenthey are connected to a first output terminal of the first rectifyingcircuit 101. A non-dotted terminal of the second winding is connected tothe switch circuit 102. The third winding and the second rectifyingcircuit 104 are connected. The backward diode has the effect of reverseclipping. An induced electromotive force generated by the first windingcan limit an amplitude of a counter electromotive force through thebackward diode, and energy caused by amplitude limitation is returned toan output of the first rectifying circuit 101 to charge the output ofthe first rectifying circuit 101. In addition, a magnetic fieldgenerated by a current passing the first winding can demagnetize a coreof the transformer so that a magnetic field strength in a transformercore is restored to an initial state. The transformer 103 is configuredto output the voltage with the second pulsating waveform based on themodulated voltage with the first pulsating waveform.

According to one embodiment of the present disclosure, as shown in FIG.1C, the power adapter may adopt a push-pull switching power supply. Ingreater detail, the transformer 103 includes a first winding, a secondwinding, a third winding, and a fourth winding. A dotted terminal of thefirst winding is connected to the switch circuit 102. A non-dottedterminal of the first winding is first connected to a dotted terminal ofthe second winding and then they are connected to a first outputterminal of the first rectifying circuit 101. A non-dotted terminal ofthe second wining is connected to the switch circuit 102. A non-dottedterminal of the third winding is connected to a dotted terminal of thefourth winding. The transformer 103 is configured to output the voltagewith the second pulsating waveform based on the modulated voltage withthe first pulsating waveform.

As shown in FIG. 1C, the switch circuit 102 includes a first MOStransistor Q1 and a second MOS transistor Q2. The transformer 103includes the first winding, the second winding, the third winding, andthe fourth winding. The dotted terminal of the first winding isconnected to a drain of the first MOS transistor Q1 in the switchcircuit 102. The non-dotted terminal of the first winding is connectedto the dotted terminal of the second winding, and a node between thenon-dotted terminal of the first winding and the dotted terminal of thesecond winding is connected to the first output terminal of the firstrectifying circuit 101. The non-dotted terminal of the second wining isconnected to a drain of the second MOS transistor Q2 in the switchcircuit 102. A source of the first MOS transistor Q1 is first connectedto a source of the second MOS transistor Q2 and then they are connectedto a second output terminal of the first rectifying circuit 101. Adotted terminal of the third winding is connected to a first inputterminal of the second rectifying circuit 104. The non-dotted terminalof the third winding is connected to the dotted terminal of the fourthwinding, and a node between the non-dotted terminal of the third windingand the dotted terminal of the fourth winding is grounded. A non-dottedterminal of the fourth winding is connected to a second input terminalof the second rectifying circuit 104.

As shown in FIG. 1C, the first input terminal of the second rectifyingcircuit 104 is connected to the dotted terminal of the third winding.The second input terminal of the second rectifying circuit 104 isconnected to the non-dotted terminal of the fourth winding. The secondrectifying circuit 104 is configured rectify the voltage with the secondpulsating waveform to output the voltage with the third pulsatingwaveform. The second rectifying circuit 104 may include two diodes. Ananode of one diode is connected to the dotted terminal of the thirdwinding. An anode of the other diode is connected to the non-dottedterminal of the fourth winding. Cathodes of the two diodes are connectedtogether.

According to one embodiment of the present disclosure, as shown in FIG.1D, the power adapter 1 may adopt a half-bridge switching power supply.In greater detail, the switch circuit 102 includes a first MOStransistor Q1, a second MOS transistor Q2, a first capacitor C1, and asecond capacitor C2. The first capacitor C1 and the second capacitor C2are first connected in series and then they are connected in parallelwith output terminals of the first rectifying circuit 101. The first MOStransistor Q1 and the second MOS transistor Q2 are first connected inseries and then they are connected in parallel with the output terminalsof the first rectifying circuit 101. The transformer 103 includes afirst winding, a second winding, and a third winding. A dotted terminalof the first winding is connected to a node between the first capacitorC1 and the second capacitor C2 connected in series. A non-dottedterminal of the first winding is connected to a node between the firstMOS transistor Q1 and the second MOS transistor Q2 connected in series.A dotted end of the second winding is connected to a first inputterminal of the second rectifying circuit 104. A non-dotted terminal ofthe second winding is first connected to a dotted terminal of the thirdwinding and then they are grounded. A non-dotted terminal of the thirdwinding is connected to a second input terminal of the second rectifyingcircuit 104. The transformer 103 is configured to output the voltagewith the second pulsating waveform based on the modulated voltage withthe first pulsating waveform.

According to one embodiment of the present disclosure, as shown in FIG.1E, the power adapter 1 may adopt a full-bridge switching power supply.In greater detail, the switch circuit 102 includes a first MOStransistor Q1, a second MOS transistor Q2, a third MOS transistor Q3,and a fourth MOS transistor Q4. The third MOS transistor Q3 and thefourth MOS transistor Q4 are first connected in series and then they areconnected in parallel with output terminals of the first rectifyingcircuit 101. The first MOS transistor Q1 and the second MOS transistorQ2 are first connected in series and then they are connected in parallelwith the output terminals of the first rectifying circuit 101. Thetransformer 103 includes a first winding, a second winding, and a thirdwinding. A dotted terminal of the first winding is connected to a nodebetween third MOS transistor Q3 and the fourth MOS transistor Q4connected in series. A non-dotted terminal of the first winding isconnected to a node between first MOS transistor Q1 and the second MOStransistor Q2 connected in series. A dotted terminal of the secondwinding is connected to a first input terminal of the second rectifyingcircuit 104. A non-dotted terminal of the second winding is firstconnected to a dotted terminal of the third winding and then they aregrounded. A non-dotted terminal of the third winding is connected to asecond input terminal of the second rectifying circuit 104. Thetransformer 103 is configured to output the voltage with the secondpulsating waveform based on the modulated voltage with the firstpulsating waveform.

Therefore, the power adapter 1 can use any of the flyback switchingpower supply, the forward switching power supply, the push pullswitching power supply, the half-bridge switching power supply, and thefull-bridge switching power supply to output the voltage with thepulsating waveform according to embodiments of the present disclosure.

In addition to that, as shown in FIG. 1A, the second rectifying circuit104 is connected to the secondary winding of the transformer 103. Thesecond rectifying circuit 104 is configured to rectify the voltage withthe second pulsating waveform to output the voltage in a third pulsatingform. The second rectifying circuit 104 may be constituted by the diodeto achieve secondary synchronous rectification so that the thirdpulsating waveform is synchronized with the modulated first pulsatingwaveform. It is noted that the third pulsating waveform beingsynchronized with the modulated first pulsating waveform refers to thatthe phase of the third pulsating waveform and the phase of the modulatedfirst pulsating waveform are consistent, and the change trend of theamplitude of the third pulsating waveform and the change trend of theamplitude of the modulated first pulsating waveform are consistent. Thefirst charging interface 105 and the second rectifying circuit 104 areconnected. The sampling circuit 106 includes a first current samplingcircuit 1061 and a first voltage sampling circuit 1062. The samplingcircuit 106 is configured to sample the voltage and/or the currentoutput from the second rectifying circuit 104 to obtain the voltagesampling value and/or the current sampling value. The control circuit107 is connected to the sampling circuit 106 and the switch circuit 102.The control circuit 107 outputs the control signal to the switch circuit102, and modulates the duty cycle of the control signal based on thevoltage sampling value and/or the current sampling value so that thevoltage with the third pulsating waveform output from the secondrectifying circuit 104 satisfies the charging requirement.

As shown in FIG. 1A, the terminal 2 includes the second charginginterface 201 and the battery 202. The second charging interface 201 isconnected to the battery 202. When the second charging interface 201 andthe first charging interface 105 are connected, the second charginginterface 201 applies the voltage with the third pulsating waveform tothe battery 202 to achieve to charging of the battery 202.

The voltage with the third pulsating waveform satisfying the chargingrequirement refers to that the voltage and a current with the thirdpulsating waveform satisfy the charging voltage and the charging currentwhen the battery is charged. That is, the control circuit 107 modulatesthe duty cycle of the control signal, such as a PWM signal, based onvoltage and/or a current output from the power adapter thus sampled toadjust an output of the second rectifying circuit 104 in a real-timemanner. A closed-loop regulation control is thus realized so that thevoltage in the third pulsation waveform satisfies the chargingrequirement of the terminal 2 to ensure that the battery 202 is safelyand reliably charged. A charging voltage waveform output to the battery202 being regulated through the duty cycle of the PWM signal is shown inFIG. 3. A charging current waveform output to the battery 202 beingregulated through the duty cycle of the PWM signal is shown in FIG. 4.

When modulating the duty cycle of the PWM signal, a regulatinginstruction can be generated based on the voltage sampling value, or thecurrent sampling value, or the voltage sampling value and the currentsampling value.

Hence, according to the embodiment of the present disclosure, thevoltage in the first pulsation waveform, that is, the voltage in theclipped pulsating waveform, which is rectified is directly modulated byperforming PWM peak clipping through controlling the switch circuit 102,and delivered to the high-frequency transformer to be coupled from theprimary side to the secondary side through the high-frequencytransformer, and then be recovered as the voltage/a current in theclipped pulsating waveform through synchronous rectification to bedirectly delivered to the battery so as to achieve the fast charging ofthe battery. An amplitude of the voltage in the clipped pulsatingwaveform can be regulated through modulating the duty cycle of the PWMsignal. As a result, the output of the power adapter satisfies thecharging requirement of the battery. It can be seen that the poweradapter according to the embodiment of the present disclosure removesthe electrolytic capacitors on the primary side and the secondary side.Through using the voltage in the clipped pulsating waveform to directlycharge the battery, the size of the power adapter can be reduced tominiaturize the power adapter and significantly reduce the cost.

In one embodiment of the present disclosure, the control circuit 107 maybe a micro controller unit (MCU). That is, the control circuit 107 maybe a microprocessor integrated with a switch-driven control function, asynchronous rectification function, and a voltage and current regulationcontrol function.

According to one embodiment of the present disclosure, the controlcircuit 107 is further configured to modulate a frequency of the controlsignal based on the voltage sampling value and/or the current samplingvalue. The PWM signal output to the switch circuit 102 can thus becontrolled to be continuously output for a period of time and then bestopped. After the output has been stopped for a predetermined time, theoutput of the PWM is turned on again. In this manner, the voltageapplied to the battery is intermittent and the battery is intermittentlycharged. As a result, the security worry caused by serious heating whenthe battery is continuously charged can be avoided to improve thereliability and safety of battery charging.

For a lithium battery, in the low temperature condition, thepolarization tends to be intensified during the charging process owingthe decline of the conductive abilities of the ions and electrons of thelithium battery itself. The continuous charging method will make thispolarization become even more obvious, and at the same time increase thepossibility of lithium precipitation, thus affecting the safeperformance of the battery. In addition, the continuous charging willresult in continuous accumulation of heat caused by charging, theinterior temperature of the battery also continuously rises. When thetemperature exceeds a certain limit value, the battery performance willbe limited and at the same time the security worry is increased.

According to the embodiment of the present disclosure, throughmodulating the frequency of the control signal, the power adapteroutputs in an intermittent manner. This situation is equivalent to thatthe stationary process of the battery is introduced during the batterycharging process, which can alleviate the possible lithium precipitationphenomenon caused by polarization in continuous charging and reduce theeffect caused by continuous accumulation of heat. The temperature isthus decreased to ensure the reliability and safety of the batterycharging.

The control signal output to the switch circuit 102 may be shown in FIG.5. The PWM signal is first continuously output for a period of time andthen is stopped for a period of time, and then is continuously outputfor a period of time. As a result, the control signal output to theswitch circuit 102 is intermittent and the frequency is adjustable.

As shown in FIG. 1A, the control circuit 107 is connected to the firstcharging interface 105. The control circuit 107 is further configured tocommunicate with the terminal 2 through the first charging interface 105to acquire state information of the terminal 2. In this manner, thecontrol circuit 107 is further configured to modulate the duty cycle ofthe control signal, such as the PWM signal, based on the stateinformation of the terminal 2, and/or the voltage sampling value and/orthe current sampling value.

The state information of the terminal 2 may include a battery level, abattery temperature, the battery voltage, interface information of theterminal, or path impedance information of the terminal, etc.

In greater detail, the first charging interface 105 includes power linesand data lines. The power lines are configured to charge the battery.The data lines are configured to communicate with the terminal 2. Whenthe second charging interface 201 is connected to the first charginginterface 105, the power adapter 1 and the terminal 2 can send acommunication inquiry instruction to each other, and establish acommunication connection between the power adapter 1 and the terminal 2after receiving a reply instruction correspondingly. The control circuit107 can acquire the state information of the terminal 2 so as tonegotiate a charging mode and the charging parameters (such as thecharging current, the charging voltage) with the terminal 2 and controlthe charging process.

The charging mode supported by the power adapter and/or the terminal mayinclude a second charging mode and a first charging mode. A charge rateof the first charging mode is greater than a charge rate of the secondcharging mode (for example, a charging current of the first chargingmode is greater than a charging current of the second charging mode).Generally speaking, the second charging mode can be understood as thecharging mode in which the rated output voltage is 5V and the ratedoutput current is less than or equal to 2.5A. In addition, in the secondcharging mode, D+ and D− in the data lines in an output port of thepower adapter may be short circuited. However, the first charging modeaccording to the embodiment of the present disclosure is different. Inthe first charging mode of the embodiment of the present disclosure, thepower adapter can communicate with the terminal by utilizing D+ and D−in the data lines to achieve data exchange, that is, the power adapterand the terminal can send a fast charging instruction to each other. Thepower adapter sends a fast charging inquiry instruction to the terminal.The power adapter acquires the state information of the terminal basedon a reply instruction of the terminal after receiving a fast chargingreply instruction of the terminal to enable the first charging mode. Inthe first charging mode, the charging current can be greater than 2.5A,for example, can be up to 4.5A or even greater. However, the secondcharging mode according to the embodiment of the present disclosure isnot limited. As long as the power adapter supports two charging modes,and a charge rate (or current) of one of the charging modes is greaterthan a charge rate of the other charging mode, the charging mode havingthe slower charge rate can be understood as the second charging mode.Regarding the charging power, the charging power corresponding to thefirst charging mode can be greater than or equal to 15 W.

The control circuit 107 communicates with the terminal 2 through thefirst charging interface 105 to determine the charging mode. Thecharging mode includes the first charging mode and the second chargingmode.

In greater detail, the power adapter and the terminal are connectedthrough a universal serial bus (USB) interface. The USB interface may bea normal USB interface, a micro USB interface, or other type USBinterfaces. Data lines in the USB interface are the data lines in thefirst charging interface and are configured to provide a bidirectionalcommunication between the power adapter and the terminal. The data linesmay be a D+ line and/or a D− line in the USB interface, and thebidirectional communication can refer to the information exchangebetween the power adapter and the terminal.

The power adapter performs the bidirectional communication with theterminal through the data lines in the USB interface to determine thatthe terminal is charged by the first charging mode.

It is noted that during the process that the power adapter negotiateswith the terminal to determine whether or not the terminal is charged bythe first charging mode, the power adapter may only be connected to theterminal and does not charge the terminal, or may charge the terminal bythe second charging mode, or may use a small current to charge theterminal. The embodiment of the present disclosure is not limited inthis regard.

The power adapter adjusts the charging current to a charging currentcorresponding to the first charging mode so as to charge the terminal.After determining to use the first charging mode to charge the terminal,the power adapter can directly adjust the charging current to thecharging current corresponding to the first charging mode, or cannegotiate with the terminal to determine the charging current of thefirst charging mode. For example, the charging current corresponding tothe first charging mode is determined based on a current power level ofthe battery in the terminal.

According to the embodiment of the present disclosure, the power adapterdoes not blindly increase the output current to perform fast charging.Rather, the power adapter needs to perform the bidirectionalcommunication with the terminal so as to negotiate whether the firstcharging mode can be used or not. As compared with the prior art, thesafety of fast charging process is increased.

Optionally, to serve as one embodiment, when the control circuitperforms the bidirectional communication with terminal through the datalines in the first charging interface to determine that the terminal ischarged by the first charging mode, the control circuit sends a firstinstruction to the terminal. The first instruction is configured toinquire of the terminal whether to enable the first charging mode ornot. The control circuit receives a reply instruction responsive to thefirst instruction from the terminal. The reply instruction responsive tothe first instruction is configured to indicate that the terminal agreesto enable the first charging mode.

Optionally, to serve as one embodiment, before the control circuit sendsthe first instruction to the terminal, the power adapter charges theterminal under the second charging mode, and the control circuit sendsthe first instruction to the terminal after determining that a chargingtime of the second charging mode is longer than a predeterminedthreshold value.

After the power adapter determines that the charging time of the secondcharging mode is longer than the predetermined threshold value, thepower adapter can assume that the terminal has identified itself as apower adapter and can enable a fast charging inquiry communication.

Optionally, to serve as one embodiment, after the power adapterdetermines to use a charging current greater than or equal to apredetermined threshold current value to charge for a predeterminedtime, the power adapter sends the first instruction to the terminal.

Optionally, to serve as one embodiment, the control circuit is furtherconfigured to control the power adapter through controlling the switchcircuit so as to adjust the charging current to the charging currentcorresponding to the first charging mode. In addition, the controlcircuit performs the bidirectional communication with the terminalthrough the data lines in the first charging interface before the poweradapter uses the charging current corresponding to the first chargingmode to charge the terminal so as to determine a charging voltagecorresponding to the first charging mode and control the power adapterto adjust the charging voltage to the charging voltage corresponding tothe first charging mode.

Optionally, to serve as one embodiment, when the control circuitperforms the bidirectional communication with the terminal through thedata lines in the first charging interface to determine the chargingvoltage corresponding to the first charging mode, the control circuitsends a second instruction to the terminal. The second instruction isconfigured to inquire whether or not a current output voltage of thepower adapter is suitable as a charging voltage of the first chargingmode. The control circuit receives a reply instruction responsive to thesecond instruction sent by the terminal. The reply instructionresponsive to the second instruction is configured to indicate that thecurrent output voltage of the power adapter is suitable, excessivelyhigh, or excessively low. The control circuit determines the chargingvoltage of the first charging mode based on the reply instructionresponsive to the second instruction.

Optionally, to serve as one embodiment, before the control circuitcontrols the power adapter to adjust the charging current to thecharging current corresponding to the first charging mode, the controlcircuit further performs the bidirectional communication with theterminal through the data lines in the first charging interface todetermine the charging current corresponding to the first charging mode.

Optionally, to serve as one embodiment, when the control circuitperforms the bidirectional communication with the terminal through thedata lines in the first charging interface to determine the chargingcurrent corresponding to the first charging mode, the control circuitsends a third instruction to the terminal. The third instruction isconfigured to inquire about a maximum charging current currentlysupported by the terminal. The control circuit receives a replyinstruction responsive to the third instruction sent by the terminal.The reply instruction responsive to the third instruction is configuredto indicate the maximum charging current currently supported by theterminal. The control circuit determines a charging current of the firstcharging mode based on the reply instruction responsive to the thirdinstruction.

The power adapter can directly determine the maximum charging current asthe charging current of the fast charge mode, or set the chargingcurrent as a current value that is less than the maximum chargingcurrent.

Optionally, to serve as one embodiment, during the process that thepower adapter is operable in the first charging mode to charge theterminal, the control circuit further performs the bidirectionalcommunication with the terminal through the data lines in the firstcharging interface to continuously adjust the charging current output tothe battery from the power adapter through controlling the switchcircuit.

The power adapter can continuously inquire about current stateinformation of the terminal, for example, inquire about the batteryvoltage, the battery power level, etc., so as to continuously adjust thecharging current output to the battery from the power adapter.

Optionally, to serve as one embodiment, when the control circuitperforms the bidirectional communication with the terminal through thedata lines in the first charging interface to continuously adjust thecharging current output to the battery from the power adapter throughcontrolling the switch circuit, the control circuit sends a fourthinstruction to the terminal. The fourth instruction is configured toinquire about a current voltage of the battery in the terminal. Thecontrol circuit receives a reply instruction responsive to the fourthinstruction sent by the terminal. The reply instruction responsive tothe fourth instruction is configured to indicate the current voltage ofthe battery in the terminal. The control circuit adjusts the chargingcurrent output to the battery from the power adapter through controllingthe switch circuit based on the current voltage of the battery.

Optionally, to serve as one embodiment, the control circuit adjusts thecharging current output to the battery from the power adapter to acharging current value corresponding to the current voltage of thebattery through controlling the switch circuit based on the currentvoltage of the battery and a predetermined relationship between abattery voltage value and a charging current value.

The power adapter can store the relationship between the battery voltagevalue and the charging current value in advance. The power adapter canperform the bidirectional communication with the terminal through thedata lines in the first charging interface to obtain the relationshipbetween the battery voltage value and the charging current value storedin the terminal from a terminal side.

Optionally, to serve as one embodiment, during the process that thepower adapter is operable in the first charging mode to charge theterminal, the control circuit further performs the bidirectionalcommunication with the terminal through the data lines in the firstcharging interface to determine whether there is a bad contact betweenthe first charging interface and the second charging interface or not.When it is determined that there is a bad contact between the firstcharging interface and the second charging interface, the controlcircuit controls the power adapter to exit the quick charging mode.

Optionally, to serve as one embodiment, before determining whether thereis a bad contact between the first charging interface and the secondcharging interface or not, the control circuit is further configured toreceive information for indicating a path impedance of the terminal fromthe terminal. The control circuit sends the fourth instruction to theterminal. The fourth instruction is configured to inquire about voltageof the battery in the terminal. The control circuit receives the replyinstruction responsive to the fourth instruction sent by the terminal.The reply instruction responsive to the fourth instruction is configuredto indicate the voltage of the battery in the terminal. The controlcircuit determines a path impedance from the power adapter to thebattery based on the output voltage of the power adapter and the voltageof the battery. The control circuit determines whether there is a badcontact between the first charging interface and the second charginginterface or not based on the path impedance from the power adapter tothe battery, the path impedance of the terminal, and a path impedance ofthe charging lines between the power adapter and the terminal.

The terminal can record the path impedance of the terminal in advance.For example, since terminals of a same model have a same structure, pathimpedances of the terminals are set as a same value in default setting.Similarly, the power adapter can record the path impedance of thecharging lines in advance. When the power adapter obtains voltage acrosstwo terminals of the battery of the terminal, a path impedance of anoverall path can be determined based on a voltage drop between the poweradapter and the two terminals of the battery and a path current. Upon ona condition that the path impedance of the overall path is greater thana sum of the path impedance of the terminal and the path impedance ofthe charging lines, or the path impedance of the overall path minus asum of the path impedance of the terminal and the path impedance of thecharging lines is greater than a threshold impedance value, it isdetermined that there is a bad contact between the first charginginterface and the second charging interface.

Optionally, to serve as one embodiment, before the power adapter exitsthe quick charging mode, the control circuit further sends a fifthinstruction to the terminal. The fifth instruction is configured toindicate that there is a bad contact between the first charginginterface and the second charging interface.

After the power adapter sends the fifth instruction, the power adaptercan exit the first charging mode or reset.

In the above, the fast charging process according to the embodiment ofthe present disclosure is described in detail from the viewpoint of thepower adapter, and the fast charging process according to the embodimentof the present disclosure is provided from the viewpoint of the terminalas follows.

Since the interactions between and relevant characteristics, functions,etc. of the power adapter and the terminal described from the terminalside are corresponding to the description from the power adapter side, arepeated description is not provided where appropriate to simplifymatters.

According to one embodiment of the present disclosure, as shown in FIG.13, the terminal 2 further includes a charging control switch 203 and acontroller 204. The charging control switch 203, such as a switchcircuit constituted by electronic switch elements, is connected betweenthe second charging interface 201 and the battery 202. The chargingcontrol switch 203 is configured to enable or end a charging process ofthe battery 202 under a control of the controller 204, so that thecharging process of the battery 202 can be controlled from the terminalside to ensure the safety and reliability of the charging of the battery202.

As shown in FIG. 14, the terminal 2 further includes a communicationcircuit 205. The communication circuit 205 is configured to establish abidirectional communication between the controller 204 and the controlcircuit 107 through the second charging interface 201 and the firstcharging interface 105. That is, the terminal 2 and the power adapter 1can perform the bidirectional communication through the data lines inthe USB interface. The terminal 2 supports the second charging mode andthe first charging mode. A charging current of the first charging modeis greater than a charging current of the second charging mode. Thecommunication circuit 205 and the control circuit 107 perform abidirectional communication to allow the power adapter 1 to determineusing the first charging mode to charge the terminal 2, so that thecontrol circuit 107 controls the power adapter 1 to output the chargingcurrent corresponding to the first charging mode to charge the battery202 in the terminal 2.

According to the embodiment of the present disclosure, the power adapter1 does not blindly increase the output current to perform fast charging.Rather, the power adapter 1 needs to perform the bidirectionalcommunication with the terminal 2 so as to negotiate whether the firstcharging mode can be used or not. As compared with the prior art, thesafety of fast charging process is improved.

Optionally, to serve as one embodiment, the controller receives a firstinstruction sent by the control circuit through the communicationcircuit. The first instruction is configured to inquire of the terminalwhether to enable the first charging mode or not. The controller sends areply instruction responsive to the first instruction to the controlcircuit through the communication circuit. The reply instructionresponsive to the first instruction is configured to indicate that theterminal agrees to enable the first charging mode.

Optionally, to serve as one embodiment, before the controller receivesthe first instruction sent by the control circuit through thecommunication circuit, the power adapter charges the battery in theterminal through the second charging mode. After the control circuitdetermines that a charging time of the second charging mode is longerthan a predetermined threshold value, the control circuit sends thefirst instruction to the communication circuit in the terminal. Thecontroller receives the first instruction sent by the control circuitthrough the communication circuit.

Optionally, to serve as one embodiment, before the power adapter outputsthe charging current corresponding to the first charging mode to chargethe battery in the terminal, the controller performs the bidirectionalcommunication with the control circuit through the communication circuitto allow the power adapter to determine the charging voltagecorresponding to the first charging mode.

Optionally, to serve as one embodiment, the controller receives a secondinstruction sent by the control circuit. The second instruction isconfigured to inquire whether or not a current output voltage of thepower adapter is suitable as the charging voltage of the first chargingmode. The controller sends a reply instruction responsive to the secondinstruction to the control circuit. The reply instruction responsive tothe second instruction is configured to indicate that the current outputvoltage of the power adapter is suitable, excessively high, orexcessively low.

Optionally, to serve as one embodiment, the controller performs thebidirectional communication with the control circuit to allow the poweradapter to determine the charging current corresponding to the firstcharging mode.

The controller receives a third instruction sent by the control circuit.The third instruction is configured to inquire about a maximum chargingcurrent currently supported by the terminal. The controller sends areply instruction responsive to the third instruction to the controlcircuit. The reply instruction responsive to the third instruction isconfigured to indicate the maximum charging current currently supportedby the battery in the terminal to allow the power adapter to determinethe charging current corresponding to the first charging mode based onthe maximum charging current.

Optionally, to serve as one embodiment, during the process that thepower adapter is operable in the first charging mode to charge theterminal, the controller performs the bidirectional communication withthe control circuit to allow the power adapter to continuously adjustthe charging current output to the battery from the power adapter.

The controller receives a fourth instruction sent by the controlcircuit. The fourth instruction is configured to inquire about a currentvoltage of the battery in the terminal. The controller sends a replyinstruction responsive to the fourth instruction to the control circuit.The reply instruction responsive to the fourth instruction is configuredto indicate the current voltage of the battery in the terminal to allowthe power adapter to continuously adjust the charging current output tothe battery from the power adapter based on the current voltage of thebattery.

Optionally, to serve as one embodiment, during the process that thepower adapter is operable in the first charging mode to charge theterminal, the controller performs the bidirectional communication withthe control circuit through the communication circuit to allow the poweradapter to determine whether there is a bad contact between the firstcharging interface and the second charging interface or not.

The controller receives the fourth instruction sent by the controlcircuit. The fourth instruction is configured to inquire about thecurrent voltage of the battery in the terminal. The controller sends thereply instruction responsive to the fourth instruction to the controlcircuit. The reply instruction responsive to the fourth instruction isconfigured to indicate the current voltage of the battery in theterminal to allow the control circuit to determine whether there is abad contact between the first charging interface and the second charginginterface or not based on the output voltage of the power adapter andthe current voltage of the battery.

Optionally, to serve as one embodiment, the controller receives a fifthinstruction sent by the control circuit. The fifth instruction isconfigured to indicate that there is a bad contact between the firstcharging interface and the second charging interface.

In order to enable and use the first charging mode, the power adaptercan perform a fast charging communication process with the terminal.Through one or more handshake negotiations, the fast charging of thebattery is achieved. A detailed description of the fast chargingcommunication process and various stages of the fast charging processaccording to the embodiment of the present disclosure is provided asfollows with reference to FIG. 6. It should be understood that thecommunication steps or operations shown in FIG. 6 are merely examples,and the embodiment of the present disclosure may further perform otheroperations or variations of the various operations in FIG. 6. Inaddition, the various stages in FIG. 6 may be performed in an orderdifferent from that presented in FIG. 6, and it may not be necessary toperform all the operations in FIG. 6. It is noted that the curve in FIG.6 is a change trend of a peak value or an average value of a chargingcurrent, rather than an actual charging current curve.

As shown in FIG. 6, the fast charging process may include five stages.

Stage 1:

After a terminal is connected to a power supply device, the terminal candetect a type of the power supply device through data lines D+, D−. Whenthe power supply device is detected as a power adapter, a currentabsorbed by the terminal may be greater than a predetermined thresholdcurrent value (for example, may be 1A). When the power adapter detectsthat an output current of the power adapter has been greater than orequal to I2 for a predetermined time (for example, may be a continuousT1 duration), the power adapter regards that the terminal has completedthe type identification of the power supply device. The power adapterturns on a handshake communication between the power adapter and theterminal. The power adapter sends an instruction 1 (corresponding to thefirst instruction as described above) to inquire of the terminal whetherto enable the first charging mode or not (or called flash charging).

When the power adapter receives a reply instruction of the terminalindicating that the terminal does not agree to enable the first chargingmode, the output current of the power adapter is detected again. Whenthe output current of the power adapter is still greater than or equalto I2 within a predetermined continuous time (for example, may be thecontinuous T1 duration), a request is sent again to inquire of theterminal whether to enable the first charging mode or not. The abovesteps of stage 1 are repeated until the terminal responds to agree toenable the first charging mode, or the output current of the poweradapter no longer satisfies the condition of being greater than or equalto I2.

The fast charging process is turned on after the terminal agrees toenable the first charging mode. The fast charging communication processenters a stage 2.

Stage 2:

Voltage in a clipped pulsating waveform output from the power adaptermay include plural levels. The power adapter sends an instruction 2(corresponding to the second instruction as described above) to theterminal to inquire of the terminal whether or not an output voltage ofthe power adapter matches a current voltage of the battery (or whetheror not suitable, that is, whether or not suitable as a charging voltageof the first charging mode), that is, whether or not satisfy thecharging requirement.

The terminal responds that the output voltage of the power adapter isexcessively high or excessively low or matching. If the power adapterreceives a feedback of the terminal that the output voltage of the poweradapter is excessively high or excessively low, the control circuitadjusts the output voltage of the power adapter by one level throughadjusting a duty cycle of a PWM signal, and sends the instruction 2 tothe terminal again to re-inquire whether the output voltage of the poweradapter matches or not.

The above steps of stage 2 are repeated until the terminal responds tothe power adapter that the output voltage of the power adapter is at amatching level, and the fast charging process enters a stage 3.

Stage 3:

After the power adapter receives the feedback replied by the terminalthat the output voltage of the power adapter is matching, the poweradapter sends an instruction 3 (corresponding to the third instructionas described above) to the terminal to inquire of the terminal a maximumcharging current currently supported by the terminal. The terminalresponds to the power adapter with the maximum charging currentcurrently supported by the terminal, and the fast charging processenters a stage 4.

Stage 4:

After the power adapter receives a feedback of the maximum chargingcurrent currently supported replied by the terminal, the power adaptercan dispose an output current reference value of the power adapter. Thecontrol circuit 107 adjusts the duty cycle of the PWM signal based theoutput current reference value so that the output current of the poweradapter satisfies the requirement of the charging current of theterminal, that is, enters the constant current stage. Here the constantcurrent stage refers to that a peak value or an average value of theoutput current of the power adapter basically remains unchanged (thatis, a change amplitude of the peak value or the average value of theoutput current is very small, for example, changes within 5% of the peakvalue or the average value of the output current). In other words, apeak value of a current in a third pulsating waveform remains constantin every period.

Stage 5:

When entering the constant current stage, the power adapter sends aninstruction 4 (corresponding to the fourth instruction as describedabove) at every interval of time to inquire of the terminal a currentvoltage. The terminal can feed back the current voltage of the batteryof the terminal to the power adapter. The power adapter can determinewhether a USB contact, that is, a contact between a first charginginterface and a second charging interface is good or not and whether itis necessary to reduce a current charging current value of the terminalor not based on a feedback of the current voltage of the battery of theterminal replied by the terminal. When the power adapter determines thatthe USB contact is bad, the power adapter sends an instruction 5(corresponding to the fifth instruction as described above) and thenresets to enter stage 1.

Optionally, in some embodiments, when the terminal responds to theinstruction 1 in stage 1, data corresponding to the instruction 1 canattach data (or information) of a path impedance of the terminal. Pathimpedance data of the terminal may be used for determining whether theUSB contact is good or not in stage 5.

Optionally, in some embodiments, time from where the terminal agrees toenable the first charging mode to where the power adapter adjusts thevoltage to an appropriate value in stage 2 can be controlled within acertain range. If the time exceeds a predetermined range, the terminalcan determine that a request is abnormal and resets quickly.

Optionally, in some embodiments, the terminal can give a feedback thatthe output voltage of the power adapter is suitable/matching to thepower adapter when the output voltage of the power adapter is adjustedto ΔV (ΔV is about 200 to 500 mV) higher than the current voltage of thebattery in stage 2. When the terminal gives a feedback that the outputvoltage of the power adapter is not suitable (that is, excessively highor excessively low) to the power adapter, the control circuit 107adjusts the duty cycle of the PWM signal based on a voltage samplingvalue to adjust the output voltage of the power adapter.

Optionally, in some embodiments, a speed of adjusting a magnitude of theoutput current of the power adapter can be controlled within a certainrange in stage 4, so as to avoid an abnormal interruption caused byexcessively fast adjustment speed.

Optionally, in some embodiments, a change amplitude of the magnitude ofthe output current of the power adapter can be controlled within 5% instage 5. That is, the constant current stage is identified.

Optionally, in some embodiments, the power adapter monitors a chargingcircuit impedance in a real-time manner in stage 5. That is, an overallcharging circuit impedance is monitored through measuring the outputvoltage of the power adapter and the current charging current, andreading a battery voltage of the terminal. When it is detected that thecharging circuit impedance is greater than a path impedance of theterminal plus an impedance of fast charging data lines, the USB contactis regarded as bad to perform a fast charging reset.

Optionally, in some embodiments, after the first charging mode enables,a communication time interval between the power adapter and the terminalcan be controlled within a certain range to avoid the fast chargingreset.

Optionally, in some embodiments, a stop of the first charging mode (orthe fast charging process) can be classified into a recoverable stop andan unrecoverable stop.

For example, when the terminal detects that the battery is full or theUSB contact is bad, the fast charging is stopped and a reset isperformed to enter stage 1. The terminal does not agree to enable thefirst charging mode. The fast charging communication process does notenter stage 2. At this time, the fast charging process that has beenstopped can be an unrecoverable stop.

In addition, for example, when there is an abnormal communicationbetween the terminal and the power adapter, the fast charging is stoppedand the reset is performed to enter stage 1. After the requirement ofstage 1 is met, the terminal agrees to enable the first charging mode torestore the fast charging process. At this time, the fast chargingprocess that has been stopped can be a recoverable stop.

Additionally, for example, when the terminal detects that the battery isabnormal, the fast charging is stopped and the reset is performed toenter stage 1. After entering stage 1, the terminal does not agree toenable the first charging mode. After the battery returns to normal andsatisfies the requirement of stage 1, the terminal agrees to enable thefirst charging mode to restore the fast charging process. At this time,the fast charging process that has been stopped can be a recoverablestop.

The communication steps or operations shown in FIG. 6 are merelyexamples. For example, in stage 1, a handshake communication between theterminal and the power adapter may be initiated by the terminal afterthe terminal is connected to the power adapter. That is, the terminalsends the instruction 1 to inquire of the power adapter whether toenable the first charging mode (or called flash charging) or not. Whenthe terminal receives a replay instruction of the power adapterindicating that the power adapter agrees to enable the first chargingmode, the fast charging process is enabled.

The communication steps or operations shown in FIG. 6 are merelyexamples. For example, a constant voltage charging stage may be furtherincluded after stage 5. That is, in stage 5, the terminal can feed backthe current voltage of the battery of the terminal to the power adapter.As voltage of the battery of the terminal rises continuously, thecharging is changed to the constant voltage charging stage when thecurrent voltage of the battery of the terminal reaches a thresholdconstant voltage charging voltage value. The control circuit 107 adjuststhe duty cycle of the PWM signal based on a voltage reference value(that is, the threshold constant voltage charging voltage value) so thatthe output voltage of the power adapter satisfies the requirement of thecharging voltage of the terminal, that is, the voltage is basicallymaintained constantly without change. In the constant voltage chargingstage, the charging current gradually decreases. When the current dropsto a certain threshold value, the charging is stopped. At this time, thebattery is identified as being fully charged. Here the constant voltagecharging refers to that a peak voltage of the third pulsating waveformis basically maintained constantly.

According to the embodiment of the present disclosure, obtaining theoutput voltage of the power adapter refers to obtaining the peak voltageor an average voltage value of the third pulsating waveform. Obtainingthe output current of the power adapter refers to obtaining a peakcurrent or an average current value of the third pulsating waveform.

According to one embodiment of the present disclosure, as shown in FIG.7A, the power adapter 1 further includes: a controllable switch 108 anda filter circuit 109 connected in series. The serially connectedcontrollable switch 108 and filter circuit 109 are connected to a firstoutput terminal of the second rectifying circuit 104. The controlcircuit 107 is further configured to control the controllable switch 108to close when a charging mode is determined to be the second chargingmode, and control the controllable switch 108 to open when the chargingmode is determined to be a first charging mode. In addition, one or moresmall capacitors are further connected in parallel at an output terminalof the second rectifying circuit 104. Not only can the noise be reduced,but the occurrence of surge phenomenon is also reduced. Or, the outputterminal of the second rectifying circuit 104 may further be connectedto an LC filter circuit or a π filter circuit to filter the rippleinterference. As shown in FIG. 7B, the output terminal of the secondrectifying circuit 104 is connected to the LC filter circuit. It isnoted that capacitors in the LC filter circuit or the π filter circuitare all small capacitors, which take a very small area.

The filter circuit 109 includes a filter capacitor. The filter capacitorcan support 5V standard charging, that is, correspond to the secondcharging mode. The controllable switch 108 may be constituted by asemiconductor switch device, such as a MOS transistor. When the poweradapter uses the second charging mode (or called standard charging) tocharge the battery in the terminal, the control circuit 107 controls thecontrollable switch 108 to close. The filter circuit 109 is connected tothe circuit so that an output of the second rectifying circuit can befiltered. In this manner, the power adapter can be better compatiblewith the DC charging technology. That is, a DC power is applied to thebattery of the terminal to achieve DC charging of the battery. Forexample, under normal circumstances, a filter circuit including anelectrolytic capacitor and an ordinary capacitor connected in parallelwould support a small capacitor required by 5V standard charging (suchas a solid state capacitor). Since the electrolytic capacitor occupies alarger volume, the electrolytic capacitor in the power adapter can beremoved to retain a capacitor having a smaller capacitance so as toreduce the size of the power adapter. When the second charging mode isused, a branch where the small capacitor is located can be controlled toconduct. The current is thus filtered to achieve a stable low-poweroutput so that the DC charging of the battery is performed. When thefirst charging mode is used, the branch where the small capacitor islocated can be controlled to disconnect. The output of the secondrectifying circuit 104 is not filtered. Voltage/current with a pulsatingwaveform is directly output to be applied to the battery, thus achievingfast charging of the battery.

With the sampling of an output current of the second rectifying circuit104, the first current sampling circuit 1061 can individually sample twocurrents flowing through two current sensing resistors, i.e. a firstresistor R1 and a second resistor R2 as illustrated in FIG. 2B, inanother embodiment of the present disclosure. The mode switch unit 115is configured to switch the first current sampling circuit 1061 tooperate in a first current sampling mode or a second current samplingmode.

The control circuit 107 is configured to control the mode switch circuit115 to control the first current sampling circuit 1061 operable in thefirst current sampling mode, when the control circuit 107 performs abidirectional communication with the terminal through the data line ofthe first charging interface to determine that the terminal is chargedby the first charging mode. The control circuit 107 is furtherconfigured to control the mode switch circuit 115 to control the firstcurrent sampling circuit 1061 operable in the second current samplingmode, when the control circuit 107 performs a bidirectionalcommunication with the terminal through the data line of the firstcharging interface to determine that the terminal is charged by thesecond charging mode.

Specifically, as FIG. 2B illustrates, the first current sampling circuit1061 includes a first resistor R1, a second resistor R2, and a currentsensor 10611 in another embodiment of the present disclosure. A firstend of the first resistor R1 is coupled to an output end of the secondrectifying circuit 104. A first end of the second resistor R2 is coupledto the output end of the second rectifying circuit 104. A third resistorR3 is coupled between the first end of the second resistor R2 and thefirst end of the first resistor R1. A fourth resistor R4 is coupledbetween a second end of the second resistor R2 and a second end of thefirst resistor R1. A resistance of the second resistor R2 is greaterthan a resistance of the first resistor R1, that is the second resistorR2 is a large resistor while the first resistor R1 is a small resistor.The current sensor 10611 is configured to sample the current outputtedby the second rectifying circuit 104 according to voltage across thefirst resistor R1 or voltage across the second resistor R2. The currentsensor 10611 can include an operational amplifier.

As FIG. 2B illustrates, the first current sampling circuit 1061 furtherincludes a fifth resistor R5, a sixth resistor R6, a first filtercapacitor C11, and a second filter capacitor C12.A first end of thefifth resistor R5 is coupled to the second end of the second resistorR2, and a second end of the fifth resistor R5 is coupled to the currentsensor 10611. A first end of the sixth resistor R6 is coupled to thesecond end of the second resistor R2, and a second end of the sixthresistor R6 is coupled to the current sensor 10611. A first end of thefirst filter capacitor C11 is coupled to the second end of the fifthresistor R5 and the current sensor 10611. A second end of the firstfilter capacitor C11 is grounded. A first end of the second filtercapacitor C12 is coupled to the second end of the sixth resistor R6 andthe current sensor 10611, and a second end of the second filtercapacitor C12 is grounded.

In other words, the first current sampling circuit 1061 can detectcurrent through the first resistor R1 (a small resistor) and the secondresistor R2 (a large resistor) individually so the first currentsampling circuit 1061 can be selectively operable in two currentsampling modes.

In another embodiment of the present disclosure, the mode switch circuit115 includes a first switch SW1 and a second switch SW2, as FIG. 2Billustrates. A first end of the first switch SW1 is coupled to thesecond end of the first resistor R1, and a control end of the firstswitch SW1 is coupled to the control circuit 107. A first end of thesecond switch SW2 is coupled to the second end of the second resistorR2, a control end of the second switch SW2 is coupled to the controlcircuit 107, and a second end of the second switch SW2 is coupled to asecond end of the first switch SW1. Both of the first switch SW1 and thesecond resistor R2 may be Metal oxide semiconductor (MOS) transistors.

In this embodiment of the present disclosure, when the control circuit107 performs a bidirectional communication with the terminal through thedata line of the first charging interface to determine that the terminalis charged by the first charging mode, i.e. a fast charging with highcurrent, the first current sampling circuit 1061 is operable in thefirst current sampling mode that current flowing through the smallresistor R1 is sensed, as the first switch SW1 turns on and the secondswitch SW2 turns off. When the control circuit 107 performs abidirectional communication with the terminal through the data line ofthe first charging interface to determine that the terminal is chargedby the second charging mode, i.e. a standard charging with low current,the first current sampling circuit 1061 is operable in the secondcurrent sampling mode that current flowing through the large resistor R2is sensed, as the first switch SW1 turns off and the second switch SW2turns on.

Accordingly, by using the charging system for the terminal according tothe present disclosure, two current sampling modes are alternativelyswitched to sample the current, which ensures the sensing function withthe compatibility between sensing precision and dynamic range andexpands the scope of the applications.

According to one embodiment of the present disclosure, the controlcircuit 107 is further configured to obtain a charging current and/or acharging voltage corresponding to the first charging mode based on stateinformation of the terminal when the charging mode is determined to bethe first charging mode, and modulate a duty cycle of a PWM signal basedon the charging current and/or the charging voltage corresponding to thefirst charging mode. That is, when a current charging mode is determinedto be the first charging mode, the control circuit 107 obtains thecharging current and/or the charging voltage corresponding to the firstcharging mode based on acquired state information of the terminal, suchas a battery voltage, a battery level, a battery temperature, operatingparameters of the terminal, and power consumption information of anapplication running on the terminal, etc., then modulates the duty cycleof a control signal based on the obtained charging current and/orcharging voltage. As a result, an output of the power adapter satisfiesthe charging requirement to achieve the fast charging of the battery.

The state information of the terminal includes the battery temperature.Additionally, when the battery temperature is higher than a firstpredetermined threshold temperature or lower than a second predeterminedthreshold temperature, the first charging mode is switched to the secondcharging mode if the current charging mode is the first charging mode.The first predetermined threshold temperature is higher the secondpredetermined threshold temperature. In other words, when the batterytemperature is excessively low (for example, the battery temperaturelower than the second predetermined threshold temperature) orexcessively high (for example, the battery temperature higher than thefirst predetermined threshold temperature), neither is suitable for fastcharging. Therefore, the first charging mode needs to be switched to thesecond charging mode. According to one embodiment of the presentdisclosure, the first predetermined threshold temperature and the secondpredetermined threshold temperature may be set or written to a memory ofthe control circuit (such as an MCU of the power adapter) depending onpractical situations.

In one embodiment of the present disclosure, the control circuit 107 isfurther configured to control the switch circuit 102 to turn off whenthe battery temperature is higher than a high temperature protectionthreshold that is predetermined. That is, the control circuit 107 needsto adopt a high temperature protection strategy to control the switchcircuit 102 to turn off when the battery temperature exceeds the hightemperature protection threshold, so that the power adapter stopscharging the battery. The high temperature protection of battery is thusachieved to improve charging safety. The high temperature protectionthreshold may be different from the first predetermined thresholdtemperature, or may be the same as the first predetermined thresholdtemperature. In at least one embodiment, the high temperature protectionthreshold is higher than the first predetermined threshold temperature.

In another embodiment of the present disclosure, a controller is furtherconfigured to acquired the battery temperature, and control a chargingcontrol switch to turn off when the battery temperature is higher thanthe high temperature protection threshold that is predetermined. Thatis, the charging control switch is turned off through a terminal side toturn off the charging process of the battery so as to ensure chargingsafety.

In one embodiment of the present disclosure, the control circuit isfurther configured to acquire a temperature of the first charginginterface, and control the switch circuit to turn off when thetemperature of the first charging interface is higher than apredetermined protection temperature. That is, the control circuit 107also needs to execute the high temperature protection strategy tocontrol the switch circuit 102 to turn off when the temperature of thefirst charging interface exceeds a certain temperature, so that thepower adapter stops charging the battery. The high temperatureprotection of charging interface is thus achieved to improve thecharging safety.

In another embodiment of the present disclosure, the controller acquiresthe temperature of the first charging interface through performing abidirectional communication with the control circuit, and controls thecharging control switch (see FIG. 13 and FIG. 14) to turn off when thetemperature of the first charging interface is higher than thepredetermined protection temperature. That is, the charging controlswitch is turned off through the terminal side to turn off the chargingprocess of the battery so as to ensure charging safety.

In greater detail, in one embodiment of the present disclosure, thepower adapter 1 further includes a drive circuit 110, such as a MOSFETdriver, as shown in FIG. 8. The drive circuit 110 is connected betweenthe switch circuit 102 and the control circuit 107. The drive circuit110 is configured to drive the switch circuit 102 to turn on or turn offbased on a control signal. Of course, it is noted that the drive circuit110 may be integrated in the control circuit 107 according to otherembodiments of the present disclosure.

As shown in FIG. 8, the power adapter 1 further includes an isolationcircuit 111. The isolation circuit 111 is connected between the drivecircuit 110 and the control circuit 107 to achieve signal isolationbetween a primary side and a secondary side of the power adapter 1 (orsignal isolation between a primary winding and a secondary winding ofthe transformer 103). The isolation circuit 111 may use an optocouplerisolation, or may use some other isolation. Through disposing theisolation circuit 111, the control circuit 107 can be disposed on thesecondary side of the power adapter 1 (or a secondary winding side ofthe transformer 103) to facilitate the control circuit 107 tocommunicate with the terminal 2. As a result, the space design of thepower adapter 1 becomes simpler and easier.

In other embodiments of the present disclosure, both the control circuit107 and the drive circuit 110 can be disposed on the primary side. Underthe circumstances, the isolation circuit 111 can be disposed between thecontrol circuit 107 and the sampling circuit 106 to achieve the signalisolation between the primary side and the secondary side of the poweradapter 1.

In one embodiment of the present disclosure, the isolation circuit 111needs to be disposed when the control circuit 107 is disposed on thesecondary side. The isolation circuit 111 may be integrated in thecontrol circuit 107. In other words, when a signal is transmitted fromthe primary side to the secondary side or from the secondary side to theprimary side, the isolation circuit usually needs to be disposed toperform signal isolation.

In one embodiment of the present disclosure, as shown in FIG. 9, thepower adapter 1 further includes an auxiliary winding and a power supplycircuit 112. The auxiliary winding generates voltage in a fourthpulsating waveform based on the voltage with the first pulsatingwaveform that is modulated. The power supply circuit 112 is connected tothe auxiliary winding. The power supply circuit 112 (for example,including a filter regulator module, a voltage conversion module, etc.)is configured to convert the voltage in the fourth pulsating waveform tooutput DC power so as to supply power to the drive circuit 110 and/orthe control circuit 107. The power supply circuit 112 may be constitutedby elements, such as a small filter capacitor, a voltage regulator chip,etc., to process and convert the voltage in the fourth pulsatingwaveform, thus outputting a low voltage DC power, such as 3.3V, or 5V,etc.

In other words, a power supply of the drive circuit 110 can be obtainedthrough converting the voltage in the fourth pulsating waveform by thepower supply circuit 112. When the control circuit 107 is disposed onthe primary side, a power supply of the control circuit 107 can beobtained through converting the voltage in the fourth pulsating waveformby the power supply circuit 112. As shown in FIG. 9, when the controlcircuit 107 is disposed on the primary side, the power supply circuit112 provides a two-way DC output to respectively supply power to thedrive circuit 110 and the control circuit 107. The isolation circuit111, e.g. an optocoupler, is disposed between the control circuit 107and the sampling circuit 106 to achieve the signal isolation between theprimary side and the secondary side of the power adapter 1.

When the control circuit 107 is disposed on the primary side and isintegrated with the drive circuit 110, the power supply circuit 112 onlysupplies power to the control circuit 107. When the control circuit 107is disposed on the secondary side and the drive circuit 110 is disposedon the primary side, the power supply circuit 112 only supplies power tothe drive circuit 110. The power of the control circuit 107 is suppliedby the secondary side, for example, a power supply circuit is used toconvert the voltage with the third pulsating waveform output from thesecond rectifying circuit 104 to a DC power so as to supply power to thecontrol circuit 107.

In one embodiment of the present disclosure, output terminals of thefirst rectifying circuit 101 are further connected in parallel with aplurality of small capacitors to have a filtering effect. Or, the outputterminals of the first rectifying circuit 101 are connected to an LCfilter circuit.

In another embodiment of the present disclosure, the power adapter 1further includes a first voltage detection circuit 113 as shown in FIG.10. The first voltage detection circuit 113 is connected to theauxiliary winding and the control circuit 107. The first voltagedetection circuit 113 is configured to detect the voltage in the fourthpulsating waveform to generate a voltage detection value. The controlcircuit 107 is further configured to modulate a duty cycle of a controlsignal based on the voltage detection value.

In other words, the control circuit 107 can reflect voltage output fromthe second rectifying circuit 104 based on voltage output from theauxiliary winding detected by the voltage detection circuit 113, andthen modulate the duty cycle of the control signal based on the voltagedetection value, so that the output of the second rectifying circuit 104matches the charging requirement of the battery.

In greater detail, in one embodiment of the present disclosure, thesampling circuit 106 includes a first current sampling circuit 1061 anda first voltage sampling circuit 1062 as shown in FIG. 11. The firstcurrent sampling circuit 1061 is configured to sample a current outputfrom the second rectifying circuit 104 to obtain a current samplingvalue. The voltage sampling circuit 1062 is configured to sample voltageoutput from the second rectifying circuit 104 to obtain voltage samplingvalue.

Optionally, the first current sampling circuit 1061 can sample voltageacross a resistor (current sensing resistor) connected to the firstoutput terminal of the second rectifying circuit 104 to achieve thesampling of the current output from the second rectifying circuit 104.The first voltage sampling circuit 1062 can sample voltage between thefirst output terminal and a second output terminal of the secondrectifying circuit 104 to achieve the sampling of the voltage outputfrom the second rectifying circuit 104.

In one embodiment of the present disclosure, the first voltage samplingcircuit 1062 includes a peak voltage sampling and retaining circuit, azero-crossing sampling circuit, a discharge circuit, and ananalog/digital (AD) sampling circuit as shown in FIG. 11. The peakvoltage sampling and retaining circuit is configured to sample andretain a peak voltage of the voltage with the third pulsating waveform.The zero-crossing sampling circuit is configured to sample zero-crossingpoints of the voltage with the third pulsating waveform. The dischargecircuit is configured to discharge the peak voltage sampling andretaining circuit at the zero-crossing points. The AD sampling circuitis configured to sample the peak voltage in the peak voltage samplingand retaining circuit so as to obtain the voltage sampling value.

Through disposing the peak voltage sampling and retaining circuit, thezero-crossing sampling circuit, the discharge circuit, and the ADsampling circuit in the first voltage sampling circuit 1062, accuratesampling of the voltage output from the second rectifying circuit 104can be achieved. In addition, the voltage sampling value can be ensuredto be synchronized with the voltage with the first pulsating waveform,that is, the phases are synchronous and the amplitude change trends areconsistent.

According to one embodiment of the present disclosure, the power adapter1 further includes a second voltage sampling circuit 114 as shown inFIG. 12. The second voltage sampling circuit 114 is configured to samplethe voltage with the first pulsating waveform. The second voltagesampling circuit 114 is connected to the control circuit 107. When avoltage value sampled by the second voltage sampling circuit 114 isgreater than a first predetermined voltage value, the control circuit107 controls the switch circuit 102 to turn on for a first predeterminedtime so as to discharge a surge voltage, a spike voltage, etc. with thefirst pulsating waveform.

As shown in FIG. 12, the second voltage sampling circuit 114 may beconnected to a first output terminal and a second output terminal of thefirst rectifying circuit 101 to achieve the sampling of the voltage withthe first pulsating waveform. The control circuit 107 makes a judgmenton the voltage value sampled by the second voltage sampling circuit 114.If the voltage value sampled by the second voltage sampling circuit 114is greater than the first predetermined voltage value, the power adapter1 is interfered with by a lighting stroke so the surge voltage appears.At This time, the surge voltage needs to be discharged to ensure thesafety and reliability of charging. The control circuit 107 controls theswitch circuit 102 to turn on for a period of time to form a dischargepath. The surge voltage caused by the lighting stroke is discharged toprevent interference caused by the lighting stroke when the poweradapter charges the terminal. As a result, the safety and reliability ofcharging the terminal is effectively improved. The first predeterminedvoltage value may be set depending on practical situations.

In one embodiment of the present disclosure, during the process that thepower adapter charges the battery 202 of the terminal 2, the controlcircuit 107 is further configured to control the switch circuit 102 toturn off when a voltage value sampled by the sampling circuit 106 isgreater than a second predetermined voltage value. That is, the controlcircuit 107 further makes a judgment on a magnitude of the voltage valuesampled by the sampling circuit 106. If the voltage value sampled by thesampling circuit 106 is greater than a second predetermined voltagevalue, voltage output from the power adapter 1 is excessively high. Atthis time, the control circuit 107 controls the switch circuit 102 toturn off so that the power adapter 1 stops charging the battery 202 ofthe terminal 2. In other words, the control circuit 107 achieves theovervoltage protection of the power adapter 1 through controlling theswitch circuit 102 to turn off so as to ensure safe charging.

In one embodiment of the present disclosure, the controller 204 performsthe bidirectional communication with the control circuit 107 to acquirethe voltage value sampled by the sampling circuit 106 (see FIG. 13 andFIG. 14), and controls the charging control switch 203 to turn off whenthe voltage value sampled by the sampling circuit 106 is greater thanthe second predetermined voltage value. That is, the charging controlswitch 203 is turned off through a side of the terminal 2 so as to turnoff the charging process of the battery 202. The charging safety isensured.

In addition, the control circuit 107 is further configured to controlthe switch circuit 102 to turn off when a current value sampled by thesampling circuit 106 is greater than a predetermined current value. Thatis, the control circuit 107 further makes a judgment on a magnitude ofthe current value sampled by the sampling circuit 106. If the currentvalue sampled by the sampling circuit 106 is greater than thepredetermined current value, a current output from the power adapter 1is excessively high. At this time, the control circuit 107 controls theswitch circuit 102 to turn off so that the power adapter 1 stopscharging the terminal 2. In other words, the control circuit 107achieves the overcurrent protection of the power adapter 1 throughcontrolling the switch circuit 102 to turn off so as to ensure safecharging.

Similarly, the controller 204 performs the bidirectional communicationwith the control circuit 107 to acquire the current value sampled by thesampling circuit 106 (see FIG. 13 and FIG. 14), and controls thecharging control switch 203 to turn off when the current value sampledby the sampling circuit 106 is greater than the predetermined currentvalue. That is, the charging control switch 203 is turned off throughthe side of the terminal 2 so as to turn off the charging process of thebattery 202. The charging safety is ensured.

Both the second predetermined voltage value and the predeterminedcurrent value may be set or written to a memory of the control circuit(for example, in the control circuit 107 of the power adapter 1, such asa micro controller unit (MCU)) depending on practical situations.

In one embodiment of the present disclosure, the terminal may be amobile terminal, such as a cellphone, a mobile power supply, such as acharging bank, a multimedia player, a notebook computer, or a wearabledevice, etc.

According to the embodiment of the present disclosure, the chargingsystem for the terminal controls the power adapter to output the voltagewith the third pulsating waveform, and directly applies the voltage withthe third pulsating waveform output from the power adapter to thebattery in the terminal, so that the fast charging of the batterydirectly by the output voltage/current that is pulsating can beachieved. A magnitude of the output voltage/current that is pulsatingchanges periodically. As compared with the disclosures of charging withconstant voltage and constant current in the related art, the lithiumprecipitation phenomenon of the lithium battery can be reduced. Theservice life of the battery can be improved. In addition, theprobability of arcing and the force of the contact at the charginginterface can further be reduced to improve the life of the charginginterface. It is also advantageous in reducing the polarization effectof the battery, improving the charging speed, reducing the battery heatso as to ensure the safety and reliability when the terminal is charged.Additionally, because the power adapter outputs the voltage with thepulsating waveform, there is no necessity to dispose electrolyticcapacitors in the power supply adapter. Not only can the power adaptersimplified and miniaturized, but the cost can also be greatly reduced.Additionally, two current sampling modes are alternatively switched tosample the current, which ensures the sensing function with thecompatibility between sensing precision and dynamic range and expandsthe scope of the applications.

In addition, the present disclosure also provides a power adapter. Thepower adapter includes a first rectifying circuit configured to rectifyan alternating current to voltage with a first pulsating waveform, aswitch circuit configured to modulate the voltage with the firstpulsating waveform according to a control signal, a transformerconfigured to output voltage with a second pulsating waveform accordingto the modulated voltage with the first pulsating waveform, a secondrectifying circuit configured to rectify the voltage with the secondpulsating waveform to voltage in a third pulsating waveform, a firstcharging interface coupled to the second rectifying circuit, a firstcurrent sampling circuit configured to sample current outputted by thesecond rectifying circuit to obtain a current sampling value, the firstcurrent sampling circuit selectively operable in a first currentsampling mode and a second current sampling mode, a mode switch circuitconfigured to control the first current sampling circuit to switchbetween the first current sampling mode and the second current samplingmode, and a control circuit coupled to the first current samplingcircuit, the mode switch circuit, and the mode switch circuit. Thecontrol circuit is configured to output the control signal to the switchcircuit, configured to control the mode switch circuit to control thefirst current sampling circuit operating in the first current samplingmode or the second current sampling mode based on a charging mode, andconfigured to regulate a duty cycle of the control signal according tothe current sampling value so that the voltage with the third pulsatingwaveform satisfies a requirement of charging. The first charginginterface is configured to apply the voltage with the third pulsatingwaveform to a battery of a terminal through a second charging interfaceof the terminal when the second charging interface of the terminalcouples to the first charging interface. The battery is coupled to thesecond charging interface.

According to the embodiment of the present disclosure, the power adapteroutputs the voltage with the third pulsating waveform through the firstcharging interface, and directly applies the voltage with the thirdpulsating waveform output from the power adapter to the battery throughthe second charging interface in the terminal, so that the fast chargingof the battery directly by the output voltage/current that is pulsatingcan be achieved. A magnitude of the output voltage/current that ispulsating changes periodically. As compared with the disclosures ofcharging with constant voltage and constant current in the related art,the lithium precipitation phenomenon of the lithium battery can bereduced. The service life of the battery can be improved. In addition,the probability of arcing and the force of the contact at the charginginterface can further be reduced to improve the life of the charginginterface. It is also advantageous in reducing the polarization effectof the battery, improving the charging speed, reducing the battery heatso as to ensure the safety and reliability when the terminal is charged.Additionally, because the power adapter outputs the voltage with thepulsating waveform, there is no necessity to dispose electrolyticcapacitors in the power supply adapter. Not only can the power adaptersimplified and miniaturized, but the cost can also be greatly reduced.Additionally, two current sampling modes are alternatively switched tosample the current, which ensures the sensing function with thecompatibility between sensing precision and dynamic range and expandsthe scope of the applications.

FIG. 15 illustrates a flowchart of a charging method for a terminalaccording to one embodiment of the present disclosure. As shown in FIG.15, the charging method for the terminal can begin at block S1.

At block S1, an AC power input to a power adapter is rectified for thefirst time to output voltage with a first pulsating waveform when afirst charging interface of the power adapter is connected to a secondcharging interface of a terminal.

That is, a first rectifying circuit in the power adapter is used torectify AC mains of an input AC power (that is, mains, such as 220V, 50Hz or 60 Hz) and output voltage in a clipped pulsating waveform of thevoltage with the first pulsating waveform (such as 100 Hz or 120 Hz).

At block S2, a switch circuit is controlled to modulate the voltage withthe first pulsating waveform, and voltage with a second pulsatingwaveform is output through transformation of a transformer.

The switch circuit may be constituted by a MOS transistor. A peakclipping modulation is performed to the voltage in the clipped pulsatingwaveform through performing a PWM control to the MOS transistor. Then,the voltage with the first pulsating waveform thus modulated is coupledto a secondary side by the transformer, and the voltage with the secondpulsating waveform is output by a secondary winding.

In one embodiment of the present disclosure, a high-frequencytransformer may be adopted to perform transformation. In this manner, asize of the transformer can be very small, thus being able to achieve ahigh-power and small-sized design of the power adapter.

At block S3, the voltage with the second pulsating waveform is rectifiedfor the second time to output voltage in a third pulsating waveform. Thevoltage with the third pulsating waveform can be applied to a battery ofthe terminal through the second charging interface to achieve thecharging of the battery of the terminal.

In one embodiment of the present disclosure, the voltage with the secondpulsating waveform is rectified for the second time through a secondrectifying circuit. The second rectifying circuit may be constituted bya diode or a MOS transistor to achieve secondary synchronousrectification so that the modulated first pulsating waveform issynchronized with the third pulsating waveform.

At block S4, current corresponding to the voltage with the thirdpulsating waveform is sampled to obtain a current sampling value. Thefirst current sampling circuit is selectively operable in a firstcurrent sampling mode and a second current sampling mode.

At block S5, the first current sampling circuit is controlled to operatein the first current sampling mode or the second current sampling modeaccording to a charging mode, while a duty cycle of the control signalapplied to the switch circuit is modulated based on the current samplingvalue so that the voltage with the third pulsating waveform satisfiesthe charging requirement.

According to another embodiment of the present disclosure, a frequencyof the control signal is regulated according to the current samplingvalue.

According to another embodiment of the present disclosure, voltageand/or current being rectified twice can be sampled to obtain a voltagesampling value and/or a current sampling value. A duty cycle of thecontrol signal applied to the switch circuit can be modulated based onthe voltage sampling value and/or the current sampling value so that thevoltage with the third pulsating waveform satisfies the chargingrequirement.

It is noted that the voltage with the third pulsating waveformsatisfying the charging requirement refers to that the voltage and acurrent with the third pulsating waveform satisfy a charging voltage anda charging current when the battery is charged. That is, the duty cycleof the control signal, such as a PWM signal, can be modulated based onvoltage and/or current output from the power adapter thus sampled toadjust an output of the power adapter in a real-time manner. Aclosed-loop regulation control is thus realized so that the voltage inthe third pulsation waveform satisfies the charging requirement of theterminal to ensure that the battery is safely and reliably charged. Thecharging voltage waveform output to the battery being regulated throughthe duty cycle of the PWM signal is shown in FIG. 3. The chargingcurrent waveform output to the battery being regulated through the dutycycle of the PWM signal is shown in FIG. 4.

Hence, according to the embodiment of the present disclosure, thevoltage in the first pulsation waveform, that is, the voltage in theclipped pulsating waveform, which is rectified by a full bridge isdirectly modulated by performing PWM peak clipping through controllingthe switch circuit, and delivered to the high-frequency transformer tobe coupled from a primary side to the secondary side through thehigh-frequency transformer, and then be recovered as the voltage/currentin the clipped pulsating waveform through synchronous rectification tobe directly delivered to the battery of the terminal so as to achievethe fast charging of the battery. An amplitude of the voltage in theclipped pulsating waveform can be regulated through adjusting the dutycycle of the PWM signal. As a result, the output of the power adaptersatisfies the charging requirement of the battery. It can be seen thatthe electrolytic capacitors on the primary side and the secondary sidein the power adapter can be removed. Through using the voltage in theclipped pulsating waveform to directly charge the battery, the size ofthe power adapter can be reduced to miniaturize the power adapter andsignificantly reduce the cost.

According to one embodiment of the present disclosure, the first currentsampling circuit is controlled to operate in the first current samplingmode, when a bidirectional communication between the terminal and thepower adapter via the first charging interface is established todetermine that the terminal is charged by the first charging mode. Thefirst current sampling circuit is controlled to operate in the secondcurrent sampling mode, when the bidirectional communication between theterminal and the power adapter via the first charging interface isestablished to determine that the terminal is charged by the secondcharging mode.

According to one embodiment of the present disclosure, a frequency ofthe control signal is modulated based on the voltage sampling valueand/or the current sampling value. The PWM signal output to the switchcircuit can thus be controlled to be continuously output for a period oftime and then be stopped. After the output has been stopped for apredetermined time, the output of the PWM is turned on again. In thismanner, the voltage applied to the battery is intermittent and thebattery is intermittently charged. As a result, the security worrycaused by serious heating when the battery is continuously charged canbe avoided to improve the reliability and safety of battery charging.The control signal output to the switch circuit may be shown in FIG. 5.

In addition to that, the charging method for the terminal furtherincludes: state information of the terminal is acquired through acommunication between the first charging interface and the terminal soas to modulate the duty cycle of the control signal based on the stateinformation of the terminal, and/or the voltage sampling value and/orthe current sampling value.

In other words, when the second charging interface is connected to thefirst charging interface, the power adapter and the terminal can send acommunication inquiry instruction to each other, and establish acommunication connection between the power adapter and the terminalafter receiving a reply instruction correspondingly. In this manner, thestate information of the terminal can be acquired so that the poweradapter negotiates a charging mode and charging parameters (such as thecharging current, the charging voltage) with the terminal and controlsthe charging process.

According to one embodiment of the present disclosure, voltage in afourth pulsating waveform is generated through transformation of thetransformer, and the voltage in the fourth pulsating waveform isdetected to generate a voltage detection value so as to modulate theduty cycle of the control signal based on the voltage detection value.

In greater detail, an auxiliary winding may be further disposed in thetransformer. The auxiliary winding can generate the voltage in thefourth pulsating waveform based on the modulated first pulsatingwaveform. In this manner, an output voltage of the power adapter can bereflected through detecting the voltage in the fourth pulsating waveformso as to modulate the duty cycle of the control signal based on thevoltage detection value. As a result, the output of the power adaptermatches the charging requirement of the battery.

In one embodiment of the present disclosure, sampling the voltage thathas been rectified twice to obtain the voltage sampling value includes:a peak voltage of the voltage that has been rectified twice is sampledand retained and zero-crossing points of the voltage that has beenrectified twice are sampled; a peak voltage sampling and retainingcircuit that samples and retains the peak voltage is discharged at thezero-crossing points; the peak voltage in the peak voltage sampling andretaining circuit is sampled to obtained the voltage sampling value.Hence, accurate sampling of the voltage output from the power adaptercan be achieved. In addition, the voltage sampling value can be ensuredto be synchronized with the voltage with the first pulsating waveform,that is, the phases the amplitude change trends are consistent.

Moreover, in one embodiment of the present disclosure, the chargingmethod for the terminal further includes: the voltage with the firstpulsating waveform is sampled and the switch circuit is controlled toturned on for a first predetermined time to discharge a surge voltagewith the first pulsating waveform when a voltage value thus sampled isgreater than a first predetermined voltage value.

Through sampling the voltage with the first pulsating waveform and thenmaking a judgment on a sampled voltage value, the power adapter isinterfered with by a lighting stroke so the surge voltage appears if thesampled voltage value is greater than the first predetermined voltagevalue. At this time, the surge voltage needs to be discharged to ensurethe safety and reliability of charging. The switch circuit needs to becontrolled to turn on for a period of time to form a discharge path. Thesurge voltage caused by the lighting stroke is discharged to preventinterference caused by the lighting stroke when the power adaptercharges the terminal. As a result, the safety and reliability ofcharging the terminal is effectively improved. The first predeterminedvoltage value may be set depending on practical situations.

According to one embodiment of the present disclosure, the charging modeis further determined through a communication between the first charginginterface and the terminal, and a charging current and/or a chargingvoltage corresponding to a first charging mode is obtained based on thestate information of the terminal when the charging mode is determinedto be the first charging mode. The duty cycle of the control signal isthus modulated based on the charging current and/or the charging voltagecorresponding to the first charging mode. The charging mode includes thefirst charging mode and a second charging mode.

In other words, when a current charging mode is determined to be thefirst charging mode, the charging current and/or the charging voltagecorresponding to the first charging mode can he obtained based onacquired state information of the terminal, such as a battery voltage, abattery level, a battery temperature, operating parameters of theterminal, and power consumption information of an application running onthe terminal, etc. Then, the duty cycle of the control signal ismodulated based on the obtained charging current and/or chargingvoltage. As a result, the output of the power adapter satisfies thecharging requirement to achieve the fast charging of the battery.

The state information of the terminal includes the battery temperature.In addition, when the battery temperature is higher than a firstpredetermined threshold temperature or lower than a second predeterminedthreshold temperature, the first charging mode is switched to the secondcharging mode if the current charging mode is the first charging mode.The first predetermined threshold temperature is higher the secondpredetermined threshold temperature. In other words, when the batterytemperature is excessively low (for example, the battery temperature islower than the second predetermined threshold temperature) orexcessively high (for example, the battery temperature is higher thanthe first predetermined threshold temperature), neither is suitable forfast charging. Therefore, the first charging mode needs to be switchedto the second charging mode. In the embodiment of the presentdisclosure, the first predetermined threshold temperature and the secondpredetermined threshold temperature may be set depending on practicalsituations.

In one embodiment of the present disclosure, the switch circuit iscontrolled to turn off when the battery temperature is higher than ahigh temperature protection threshold that is predetermined. That is, ahigh temperature protection strategy needs to be adopted to control theswitch circuit to turn off when the battery temperature exceeds the hightemperature protection threshold, so that the power adapter stopscharging the battery. The high temperature protection of battery is thusachieved to improve charging safety. The high temperature protectionthreshold may be different from the first predetermined thresholdtemperature, or may be the same as the first predetermined thresholdtemperature. In at least one embodiment, the high temperature protectionthreshold is higher than the first predetermined threshold temperature.

In another embodiment of the present disclosure, the terminal furtheracquires the battery temperature, and controls the battery by stoppingthe charging when the battery temperature is higher than the hightemperature protection threshold that is predetermined. That is, acharging control switch can be turned off through a terminal side to endthe charging process of the battery so as to ensure charging safety.

In one embodiment of the present disclosure, the charging method for theterminal further includes: a temperature of the first charging interfaceis acquired, and the switch circuit is controlled to turned off when thetemperature of the first charging interface is higher than apredetermined protection temperature. That is, the control circuit alsoneeds to execute the high temperature protection strategy to control theswitch circuit to turn off when the temperature of the first charginginterface exceeds a certain temperature, so that the power adapter stopscharging the battery. The high temperature protection of charginginterface is thus achieved to improve the charging safety.

In another embodiment of the present disclosure, the terminal acquiresthe temperature of the first charging interface by performing abidirectional communication with the power adapter through the secondcharging interface, and controls the battery by stopping the chargingwhen the temperature of the first charging interface is higher than thepredetermined protection temperature. That is, the charging controlswitch can be turned off through the terminal side to end the chargingprocess of the battery so as to ensure charging safety.

During the process that the power adapter charges the terminal, theswitch circuit is controlled to turn off when the voltage sampling valueis greater than a second predetermined voltage value. That is, duringthe process that the power adapter charges the terminal, a judgment isfurther made on a magnitude of the voltage sampling value. If thevoltage sampling value is greater than the second predetermined voltagevalue, the voltage output from the power adapter is excessively high. Atthis time, the switch circuit is controlled to turn off so that thepower adapter stops charging the terminal. In other words, theovervoltage protection of the power adapter is achieved throughcontrolling the switch circuit to turn off so as to ensure safecharging.

In one embodiment of the present disclosure, the terminal acquires thevoltage sampling value by performing the bidirectional communicationwith the power adapter through the second charging interface, andcontrols the battery by stopping the charging when the voltage samplingvalue is greater than the second predetermined voltage value. That is,the charging control switch can be turned off through the terminal sideso as to end the charging process of the battery. The charging safety isensured.

In one embodiment of the present disclosure, during the process that thepower adapter charges the terminal, the switch circuit is controlled toturn off when the current sampling value is greater than a predeterminedcurrent value. That is, during the process that the power adaptercharges the terminal, a judgment is further made on a magnitude of thecurrent sampling value. If the current sampling value is greater thanthe predetermined current value, the current output from the poweradapter is excessively high. At this time, the switch circuit iscontrolled to turn off so that the power adapter stops charging theterminal. In other words, the overcurrent protection of the poweradapter is achieved through controlling the switch circuit to turn offso as to ensure safe charging.

Similarly, the terminal acquires the current sampling value byperforming the bidirectional communication with the power adapterthrough the second charging interface, and controls the battery bystopping the charging when the current sampling value is greater thanthe predetermined current value. That is, the charging control switchcan be turned off through the terminal side so as to end the chargingprocess of the battery. The charging safety is ensured.

Both the second predetermined voltage value and the predeterminedcurrent value may be set depending on practical situations.

In one embodiment of the present disclosure, the state information ofthe terminal comprises a battery level, a battery temperature,voltage/current of the terminal, interface information of the terminal,or path impedance information of the terminal.

In greater detail, the power adapter and the terminal are connectedthrough a universal serial bus (USB) interface. The USB interface may bea normal USB interface, or may be a micro USB interface. Data lines inthe USB interface are the data lines in the first charging interface andare configured to provide a bidirectional communication between thepower adapter and the terminal. The data lines may be a D+ line and/or aD− line in the USB interface, and the bidirectional communication canrefer to the information exchange between the power adapter and theterminal.

The power adapter performs the bidirectional communication with theterminal through the data lines in the USB interface to determine thatthe terminal is charged by the first charging mode.

Optionally, in some embodiments, when a bidirectional communicationbetween the terminal and the first charging interface is established todetermine that the terminal is charged by the first charging mode, afirst instruction, configured to inquire of the terminal whether toenable the first charging mode or not, is sent to the terminal by thepower adapter, and a reply instruction responsive to the firstinstruction from the terminal, configured to indicate that the terminalagrees to enable the first charging mode, is received by the poweradapter.

Optionally, in some embodiments, before sending the first instruction tothe terminal, the power adapter charges the terminal through the secondcharging mode, the first instruction is sent to the terminal if acharging time of the second charging mode is longer than a predeterminedthreshold value.

It is noted that if a charging time of the second charging mode islonger than a predetermined threshold value, the power adapterdetermines that the terminal has identified the power adapter and canenable fast charging inquiry.

Optionally, in some embodiments, before a charging current of the poweradapter is adjusted to a charging current corresponding to the firstcharging mode by controlling the switch circuit, and the power adapteruses the charging current corresponding to the first charging mode tocharge the terminal, a charging voltage corresponding to the firstcharging mode is determined through the bidirectional communicationbetween the terminal and the power adapter via the first charginginterface. The power adapter is controlled to adjust a charging voltageto the charging voltage corresponding to the first charging mode.

Optionally, in some embodiments, the determining a charging voltagecorresponding to the first charging mode through the bidirectionalcommunication between the terminal and the power adapter via the firstcharging interface includes: a second instruction that is configured toinquire whether or not a current output voltage of the power adapter issuitable as a charging voltage of the first charging mode is sent to theterminal by the power adapter, and a reply instruction responsive to thesecond instruction sent by the terminal is received by the poweradapter. The reply instruction responsive to the second instruction isconfigured to indicate that the current output voltage of the poweradapter is suitable, excessively high, or excessively low. Then thecharging voltage of the first charging mode is determined by the poweradapter based on the reply instruction responsive to the secondinstruction.

Optionally, in some embodiments, before the charging current of thepower adapter is adjusted to the charging current corresponding to thefirst charging mode, the charging current corresponding to the firstcharging mode is determined through the bidirectional communicationbetween the terminal and the power adapter via the first charginginterface.

Optionally, in some embodiments, the determining the charging currentcorresponding to the first charging mode through the bidirectionalcommunication between the terminal and the power adapter via the firstcharging interface includes: a third instruction to the terminal is sentby the power adapter, a reply instruction responsive to the thirdinstruction sent by the terminal is received by the power adapter, and acharging current of the first charging mode is determined based on thereply instruction responsive to the third instruction. The thirdinstruction is configured to inquire about a maximum charging currentcurrently supported by the terminal. The reply instruction responsive tothe third instruction configured to indicate the maximum chargingcurrent currently supported by the terminal.

The power adapter can set the maximum charging current as the chargingcurrent of the first charging mode, or any charging current less thanmaximum charging current as the charging current of the first chargingmode.

Optionally, in some embodiments, during the process that the poweradapter is operable in the first charging mode to charge the terminal,the charging current output to the battery from the power adapter iscontinuously adjusted by controlling the switch circuit through thebidirectional communication between the terminal and the power adaptervia the first charging interface.

The power adapter can continuously inquiry the current state informationof the terminal, such as battery voltage or power volume of the battery,so as to continuously adjust the charging current.

Optionally, in some embodiments, the continuously adjusting the chargingcurrent output to the battery from the power adapter through controllingthe switch circuit through the bidirectional communication between theterminal and the power adapter via the first charging interface,includes: a fourth instruction to the terminal is sent by the poweradapter, a reply instruction responsive to the fourth instruction sentfrom the terminal is received by the power adapter, and the chargingcurrent is adjusted through controlling the switch circuit based on thecurrent voltage of the battery. The fourth instruction is configured toinquire about a current voltage of the battery in the terminal. Thereply instruction responsive to the fourth instruction configured toindicate the current voltage of the battery in the terminal.

Optionally, in some embodiments, the adjusting the charging currentthrough controlling the switch circuit based on the current voltage ofthe battery, includes: the charging current output to the battery fromthe power adapter is adjusted to a charging current value correspondingto the current voltage of the battery through controlling the switchcircuit based on the current voltage of the battery and a predeterminedrelationship between a battery voltage value and a charging currentvalue.

Optionally, the power adapter can store a relationship between thebattery voltage and charging current.

Optionally, in some embodiments, during the process that the poweradapter is operable in the first charging mode to charge the terminal,it is determined that whether there is a bad contact between the firstcharging interface and a second charging interface or not, through thebidirectional communication between the terminal and the power adaptervia the first charging interface. The power adapter is controlled toexit the first charging mode when it is determined that there is a badcontact between the first charging interface and the second charginginterface.

Optionally, in some embodiments, before determining whether there is abad contact between the first charging interface and the second charginginterface or not, an information indicative of a path impedance of theterminal from the terminal is received. The receiving informationindicative of a path impedance of the terminal from the terminalincludes: a fourth instruction to the terminal is sent by the poweradapter, a reply instruction responsive to the fourth instruction sentby the terminal is received by the power adapter, a path impedance fromthe power adapter to the battery is determined based on an outputvoltage of the power adapter and the voltage of the battery, and it isdetermined whether there is a bad contact between the first charginginterface and the second charging interface or not based on the pathimpedance from the power adapter to the battery, the path impedance ofthe terminal, and a path impedance of charging lines between the poweradapter and the terminal. The fourth instruction is configured toinquire about voltage of the battery in the terminal. The replyinstruction responsive to the fourth instruction is configured toindicate the voltage of the battery in the terminal.

Optionally, in some embodiments, before the power adapter is controlledto exit the first charging mode, a fifth instruction is sent to theterminal. The fifth instruction is configured to indicate that there isa bad contact between the first charging interface and the secondcharging interface.

After sending the fifth instruction, the power adapter can exit rapidlyand reset.

The description of fast charging process in the above paragraphs is inview of the power adapter. The following describes the fast chargingprocess in view of the terminal.

According to the present disclosure, the terminal supports the secondcharging mode and the first charging mode. A charging current of thefirst charging mode is greater than a charging current of the secondcharging mode. The power adapter determines that the first charging modeis used to charge the terminal, through the bidirectional communicationbetween the second charging interface of the terminal and the adapter.The power adapter outputs the charging current corresponding to thefirst charging mode to charge the battery in the terminal.

Optionally, in some embodiments, determining that the first chargingmode is used to charge the terminal, through the bidirectionalcommunication between the second charging interface of the terminal andthe adapter, includes: the terminal receives a first instruction sentfrom the power adapter, the first instruction configured to inquire ofthe terminal whether to enable the first charging mode or not; theterminal sends a reply instruction responsive to the first instructionto the power adapter, the reply instruction responsive to the firstinstruction configured to indicate that the terminal agrees to enablethe first charging mode.

Optionally, in some embodiments, before receiving the first instructionsent from the power adapter, the power adapter charges the terminalthrough the second charging mode. The terminal receives the firstinstruction sent from the power adapter if a charging time of the secondcharging mode is longer than a predetermined threshold value.

Optionally, in some embodiments, before a charging current of the poweradapter is adjusted to a charging current corresponding to the firstcharging mode, and the power adapter uses the charging currentcorresponding to the first charging mode to charge the terminal, thecharging voltage corresponding to the first charging mode is determinedthrough the bidirectional communication between the power adapter andthe second charging interface of the terminal.

Optionally, in some embodiments, determining the charging voltagecorresponding to the first charging mode through the bidirectionalcommunication between the power adapter and the second charginginterface of the terminal, includes: the terminal receives a secondinstruction sent by the power adapter, the second instruction configuredto inquire whether or not a current output voltage of the power adapteris suitable as a charging voltage of the first charging mode; theterminal sends a reply instruction responsive to the second instructionto the power adapter, the reply instruction responsive to the secondinstruction configured to indicate that the current output voltage ofthe power adapter is suitable, excessively high, or excessively low.

Optionally, in some embodiments, before the charging current of thepower adapter is adjusted to the charging current corresponding to thefirst charging mode, and the terminal uses the charging currentcorresponding to the first charging mode to charge the battery, thepower adapter determines the charging current corresponding to the firstcharging mode through the bidirectional communication between the poweradapter and the second charging interface of the terminal.

Optionally, in some embodiments, the power adapter determines thecharging current corresponding to the first charging mode through thebidirectional communication between the power adapter and the secondcharging interface of the terminal, includes: the terminal receives athird instruction sent by the power adapter, the third instructionconfigured to inquire about a maximum charging current currentlysupported by the terminal; the terminal sends a reply instructionresponsive to the third instruction to the power adapter, the replyinstruction responsive to the third instruction configured to indicatethe maximum charging current currently supported by the terminal toallow the power adapter to determine the charging current correspondingto the first charging mode based on the maximum charging current.

Optionally, in some embodiments, during the process that the poweradapter is operable in the first charging mode to charge the terminal,the power adapter continuously adjusts the charging current output tothe battery from the power adapter through the bidirectionalcommunication between the terminal and the power adapter via the firstcharging interface.

Optionally, in some embodiments, continuously adjusting the chargingcurrent output to the battery from the power adapter through thebidirectional communication between the terminal and the power adaptervia the first charging interface, includes: the terminal receives afourth instruction sent by the power adapter, the fourth instructionconfigured to inquire about a current voltage of the battery in theterminal; the terminal sends a reply instruction responsive to thefourth instruction to the power adapter, the reply instructionresponsive to the fourth instruction configured to indicate the currentvoltage of the battery in the terminal to allow the power adapter tocontinuously adjust the charging current output to the battery from thepower adapter based on the current voltage of the battery.

Optionally, in some embodiments, during the process that the poweradapter is operable in the first charging mode to charge the terminal,the power adapter determines whether there is a bad contact between thefirst charging interface and the second charging interface or notthrough the bidirectional communication between the second charginginterface and the power adapter.

Optionally, in some embodiments, determining whether there is a badcontact between the first charging interface and the second charginginterface or not through the bidirectional communication between thesecond charging interface and the power adapter, includes: the terminalreceives a fourth instruction sent by the power adapter, the fourthinstruction configured to inquire about a current voltage of the batteryin the terminal; the terminal sends a reply instruction responsive tothe fourth instruction to the control circuit, the reply instructionresponsive to the fourth instruction configured to indicate the currentvoltage of the battery in the terminal to allow the power adapter todetermine whether there is a bad contact between the first charginginterface and the second charging interface or not based on the outputvoltage of the power adapter and the current voltage of the battery.

Optionally, in some embodiments, the terminal receives a fifthinstruction sent by the power adapter. The fifth instruction isconfigured to indicate that there is a bad contact between the firstcharging interface and the second charging interface.

In order to enable the first charging mode, the power adapter canperform a fast charging communication process with the terminal. Throughone or more handshake negotiations, the fast charging of the battery isachieved. A detailed description of the fast charging communicationprocess and various stages of the fast charging process according to theembodiment of the present disclosure is provided as follows withreference to FIG. 6. It should be understood that the communicationsteps or operations shown in FIG. 6 are merely examples, and theembodiment of the present disclosure may further perform otheroperations or variations of the various operations in FIG. 6. Inaddition, the various stages in FIG. 6 may be performed in an orderdifferent from that presented in FIG. 6, and it may not be necessary toperform all the operations in FIG. 6.

In summary, according to the embodiment of the present disclosure, thecharging method for the terminal controls the power adapter to outputthe voltage with the third pulsating waveform that satisfies thecharging requirement, and directly applies the voltage with the thirdpulsating waveform output from the power adapter to the battery in theterminal, so that the fast charging of the battery directly by theoutput voltage/current that is pulsating can be achieved. A magnitude ofthe output voltage/current that is pulsating changes periodically. Ascompared with the disclosure of charging with constant voltage andconstant current in the related art, the lithium precipitationphenomenon of the lithium battery can be reduced. The service life ofthe battery can be improved. In addition, the probability of arcing andthe force of the contact at the charging interface can further bereduced to improve the life of the charging interface. It is alsoadvantageous in reducing the polarization effect of the battery,improving the charging speed, reducing the battery heat so as to ensurethe safety and reliability when the terminal is charged. Additionally,because the power adapter outputs the voltage with the pulsatingwaveform, there is no necessity to dispose electrolytic capacitors inthe power adapter. Not only can the power adapter be simplified andminiaturized, but the cost can also be greatly reduced. Additionally,two current sampling modes are alternatively switched to sample thecurrent, which ensures the sensing function with the compatibilitybetween sensing precision and dynamic range and expands the scope of theapplications.

In the disclosure, it is should be understood that spatially relativeterms, such as “center”, “longitudinal”, “lateral”, “length”, “width”,“above”, “below”, “front”, “back”, “left”, “right”, “horizontal”,“vertical”, “top”, “bottom”, “inner”, “outer”, “clockwise”,“counterclockwise”, “axial”, “radial”, “circumferential”, and the like,may be used herein for ease of description to describe one element orfeature's relationship to another element(s) or feature(s) asillustrated in the figures. It will be understood that the spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The spatially relative terms are not limited to specificorientations depicted in the figures.

In addition, the term “first”, “second” are for illustrative purposesonly and are not to be construed as indicating or imposing a relativeimportance or implicitly indicating the number of technical featuresindicated. Thus, a feature that limited by “first”, “second” mayexpressly or implicitly include at least one of the features. In thedescription of the present disclosure, the meaning of “plural” is two ormore, unless otherwise specifically defined.

All of the terminologies containing one or more technical or scientificterminologies have the same meanings that persons skilled in the artunderstand ordinarily unless they are not defined otherwise. Forexample, “arrange,” “couple,” and “connect,” should be understoodgenerally in the embodiments of the present disclosure. For example,“firmly connect,” “detachably connect,” and “integrally connect” are allpossible. It is also possible that “mechanically connect,” “electricallyconnect,” and “mutually communicate” are used. It is also possible that“directly couple,” “indirectly couple via a medium,” and “two componentsmutually interact” are used.

All of the terminologies containing one or more technical or scientificterminologies have the same meanings that persons skilled in the artunderstand ordinarily unless they are not defined otherwise. Forexample, “upper” or “lower” of a first characteristic and a secondcharacteristic may include a direct touch between the first and secondcharacteristics. The first and second characteristics are not directlytouched; instead, the first and second characteristics are touched viaother characteristics between the first and second characteristics.Besides, the first characteristic arranged on/above/over the secondcharacteristic implies that the first characteristic arranged rightabove/obliquely above or merely means that the level of the firstcharacteristic is higher than the level of the second characteristic.The first characteristic arranged under/below/beneath the secondcharacteristic implies that the first characteristic arranged rightunder/obliquely under or merely means that the level of the firstcharacteristic is lower than the level of the second characteristic.

In the description of this specification, the description of the terms“one embodiment”, “some embodiments”, “examples”, “specific examples”,or “some examples”, and the like, means to refer to the specificfeature, structure, material or characteristic described in connectionwith the embodiments or examples being included in at least oneembodiment or example of the present disclosure. In the presentspecification, the term of the above schematic representation is notnecessary for the same embodiment or example. Furthermore, the specificfeature, structure, material, or characteristic described may be incombination in a suitable manner in any one or more of the embodimentsor examples. In addition, it will be apparent to those skilled in theart that different embodiments or examples described in thisspecification, as well as features of different embodiments or examples,may be combined without contradictory circumstances.

One having ordinary skill in the art may be aware that the units andsteps of algorithm in the examples of the embodiments published by thisapplication can be realized by electronic hardware, or combinations ofcomputer software and electronic hardware. Whether the functions shouldbe performed by hardware or software should depend upon the particularapplications and design constraints of a technical solution. One skilledin the art may use different methods to implement the describedfunctions for each specific application, but such implementation shouldnot be considered as outside of the scope of the present disclosure.

One skilled in the art may clearly understand that they can refer to thecorresponding process in the abovementioned embodiments of the methodfor the specific operating process of the abovementioned system, device,and circuits. No description is provided herein again for theconvenience and succinctness of the description.

In the several embodiments provided by the application, it should beunderstood that the revealed system, device and method may beimplemented in other ways. For example, the abovementioned embodimentsof the device are merely schematic. For example, the division of thecircuits is merely a division based on logical functions; it may bedifferent when they are put into practice. For example, a plurality ofcircuits or components may be combined or integrated into anothersystem, or some features may be ignored or not be performed. And anotherpoint is that the displayed or discussed coupling, direct coupling orcommunication can be done through some interfaces, devices, or indirectcoupling or communication between circuits; they may be electrical,mechanical, or in other forms.

The circuits described as separated parts may or may not be physicallyseparated. A part that appeared as a circuit may or may not be aphysical circuit, i.e. it can locate in one place, or it can bedistributed to multiple network circuits. Part of or all of the circuitscan be selected based on actual needs to achieve the object of thesolutions of the present embodiments.

Furthermore, each of the functional circuits in the embodiments of thepresent disclosure may be integrated in one processing circuit, or maybe independent circuits physically separated, or may integrate withanother one or more circuits and appear as a single circuit.

If the function is realized as a software functional unit and used orsold as a standalone product, it may be stored in a computer-readablestorage medium. Based on such understanding, the technical solutions ofthe present disclosure per se, or its contribution to the related art,or the technical solution may be realized in a software product. Thecomputer software product is stored in a storage medium, includingseveral commands that enable a computer device (may be a personalcomputer, a server, or network device) to perform all or part of thesteps of the methods of the various embodiments of the presentdisclosure. The storage medium includes U-disk, removable hard disk,read-only memory (ROM), random access memory (RAM), magnetic disk orcompact disc (CD) and other medium that can store program codes.

The above texts are merely specific embodiments of the presentdisclosure. However, the scope of the present disclosure is not limitedhereto. Any variations or alternatives that can easily be thought of bytechnicians familiar with the field should fall within the scope of thepresent disclosure. Therefore, the scope of the present disclosureshould be defined by the scope of the claims.

1. A charging system, comprising: a battery; a first rectifying circuit,configured to rectify an alternating current to voltage with a firstpulsating waveform; a switch circuit, configured to modulate the voltagewith the first pulsating waveform according to a control signal; atransformer, configured to output voltage with a second pulsatingwaveform according to the modulated voltage with the first pulsatingwaveform; a second rectifying circuit, configured to rectify the voltagewith the second pulsating waveform to voltage with a third pulsatingwaveform; a first current sampling circuit, configured to sample currentoutputted by the second rectifying circuit to obtain a current samplingvalue, the first current sampling circuit selectively operable in afirst current sampling mode and a second current sampling mode; a modeswitch circuit, configured to control the first current sampling circuitto switch between the first current sampling mode and the, secondcurrent sampling mode; and a control circuit, coupled to the firstcurrent sampling circuit, the mode switch circuit, and the mode switchcircuit, the control circuit configured to output the control signal tothe switch circuit, configured to control the mode switch circuit tocontrol the first current sampling circuit operating in the firstcurrent sampling mode or the second current sampling mode based on acharging mode, and configured to regulate a duty cycle of the controlsignal according to the current sampling value so that the voltage withthe third pulsating waveform satisfies a requirement of charging thebattery. and 2-31. (canceled)
 32. An power adapter, comprising: a firstrectifying circuit, configured to rectify an alternating current tovoltage with a first pulsating waveform; a switch circuit, configured tomodulate the voltage with the first pulsating waveform according to acontrol signal; a transformer, configured to output voltage with asecond pulsating waveform according to the modulated voltage with thefirst pulsating waveform; a second rectifying circuit, configured torectify the voltage with the second pulsating waveform to voltage with athird pulsating waveform; a first charging interface, coupled to thesecond rectifying circuit and configured to apply the voltage with thethird pulsating waveform to a battery of a terminal through a secondcharging interface of the terminal when the second charging interface ofthe terminal couples to the first charging interface, wherein thebattery is coupled to the second charging interface; a first currentsampling circuit, configured to sample current outputted by the secondrectifying circuit to obtain a current sampling value, the first currentsampling circuit selectively operable in a first current sampling modeand a second current sampling mode; a mode switch circuit, configured tocontrol the first current sampling circuit to switch between the firstcurrent sampling mode and the second current sampling mode; and acontrol circuit, coupled to the first current sampling circuit, the modeswitch circuit, and the switch circuit, the control circuit configuredto output the control signal to the switch circuit, configured tocontrol the mode switch circuit to control the first current samplingcircuit operating in the first current sampling mode or the secondcurrent sampling mode based on a charging mode, and configured toregulate a duty cycle of the control signal according to the currentsampling value so that the voltage with the third. pulsating waveformsatisfies a requirement of charging.
 33. The power adapter as claimed inclaim 32, wherein the control circuit is further configured to regulatea frequency of the control signal according to the current samplingvalue.
 34. The power adapter as claimed in claim 32, wherein thecharging interface comprises a power line configured to charge thebattery and a data line configured to communicate with the terminal; thecontrol circuit communicates with the terminal through the firstcharging interface to determine the charging mode that comprises a firstcharging mode and a second charging mode.
 35. The power adapter asclaimed in claim 34, wherein the control circuit is further configuredto control the mode switch circuit to control the first current samplingcircuit operable in the first current sampling mode, when the controlcircuit performs a bidirectional communication with the terminal throughthe data line of the first charging interface to determine that theterminal is charged by the first charging mode; and the control circuitis further configured to control the mode switch circuit to control thefirst current sampling circuit operable in the second current samplingmode, when the control circuit performs a bidirectional communicationwith the terminal through the data line of the first charging interfaceto determine that the terminal is charged by the second charging mode.36. The power adapter as claimed in claim 32, wherein the first currentsampling circuit comprises: a first resistor, a first end of the firstresistor coupled to an output end of the second rectifying circuit; asecond resistor, a first end of the second resistor coupled to theoutput end of the second rectifying circuit, wherein a resistance of thesecond resistor is greater than a resistance of the first resistor; athird resistor, coupled between the first end of the second resistor andthe first end of the first resistor; a fourth resistor, coupled betweena second end of the second resistor and a second end of the firstresistor; and a current sensor, configured to sample the currentoutputted by the second rectifying circuit according to voltage acrossthe first resistor or voltage across the second resistor.
 37. The poweradapter as claimed in claim 36, wherein the first current samplingcircuit further comprises: a fifth resistor, a first end of the fifthresistor coupled to the second end of the second resistor and a secondend of the fifth resistor coupled to the current sensor; a sixthresistor, a first end of the sixth resistor coupled to the second end ofthe second resistor, and a second end of the sixth resistor coupled tothe current sensor; a first filter capacitor, a first end of the firstfilter capacitor coupled to the second end of the fifth resistor and thecurrent sensor and a second end of the first filter capacitor beinggrounded; and a second filter capacitor, a first end of the secondfilter capacitor coupled to the second end of the sixth resistor and thecurrent sensor, and a second end of the second filter capacitor beinggrounded.
 38. The power adapter as claimed in claim 36, wherein the modeswitch circuit comprises: a first switch, a first end of the firstswitch coupled to the second end of the first resistor, and a controlend of the first switch coupled to the control circuit; a second switch,a first end of the second switch coupled to the second end of the secondresistor, a control end of the second switch coupled to the controlcircuit, and a second end of the second switch coupled to a second endof the first switch.
 39. The power adapter as claimed in claim 34,wherein when the control. circuit performs a bidirectional communicationwith the terminal through the data lines in the first charging interfaceto determine that the terminal is charged by the first charging mode,the control circuit sends a first instruction to the terminal, the firstinstruction is configured to inquire of the terminal whether to enablethe first charging mode or not; the control circuit receives a replyinstruction responsive to the first instruction from the terminal, thereply instruction responsive to the first instruction is configured toindicate that the terminal agrees to enable the first charging mode. 40.The power adapter as claimed in claim 39, wherein before the controlcircuit sends the first instruction to the terminal, the power adaptercharges the terminal through the second charging mode, and the controlcircuit sends the first instruction to the terminal after determiningthat a charging time of the second charging mode is longer than apredetermined threshold value.
 41. The power adapter as claimed in claim39, wherein the control circuit is further configured to control thepower adapter through controlling the switch. circuit so as to adjust acharging current to a charging current corresponding to the firstcharging mode, and before the power adapter uses the charging currentcorresponding to the first charging mode to charge the terminal, thecontrol circuit performs the bidirectional communication with theterminal through the data lines in the first charging interface todetermine a charging voltage corresponding to the first charging modeand control the power adapter to adjust a charging voltage to thecharging voltage corresponding to the first charging mode.
 42. The poweradapter as claimed in claim 41, wherein when the control circuitperforms the bidirectional communication with the terminal through thedata lines in the first charging interface to determine the chargingvoltage corresponding to the first charging mode, the control circuitsends a second instruction to the terminal, the second instruction isconfigured to inquire whether or not a current output voltage of thepower adapter is suitable as a charging voltage of the first chargingmode; the control circuit receives a reply instruction responsive to thesecond instruction sent by the terminal, the reply instructionresponsive to the second instruction is configured to indicate that thecurrent output voltage of the power adapter is suitable, excessivelyhigh, or excessively low; the control circuit determines the chargingvoltage of the first charging mode based on the reply instructionresponsive to the second instruction.
 43. The power adapter as claimedin claim 41, wherein before the control circuit controls the poweradapter to adjust the charging current to the charging currentcorresponding to the first charging mode, the control circuit furtherperforms the bidirectional communication with the terminal through thedata lines in the first charging interface to determine the chargingcurrent corresponding to the first charging mode.
 44. The power adapteras claimed in claim 43, wherein when the control circuit performs thebidirectional communication with the terminal through the data lines inthe first charging interface to determine the charging currentcorresponding to the first charging mode, the control circuit sends athird instruction to the terminal, the third instruction is configuredto inquire about a maximum charging current currently supported by theterminal; the control circuit receives a reply instruction responsive tothe third instruction sent by the terminal, the reply instructionresponsive to the third instruction is configured to indicate themaximum charging current currently supported by the terminal; thecontrol circuit determines a charging current of the first charging modebased on the reply instruction responsive to the third instruction. 45.The power adapter as claimed in claim 39, wherein during the processthat the power adapter is operable in the first charging mode to chargethe terminal, the control circuit further performs the bidirectionalcommunication with the terminal through the data lines in the firstcharging interface to continuously adjust the charging current output tothe battery from the power adapter through controlling the switchcircuit, 46-50. (canceled)
 51. A charging method of charging a terminal,comprising: rectifying an alternating current to output voltage with afirst pulsating waveform when a first charging interface of a poweradapter couples a second charging interface of the terminal; modulating,by controlling a mode switch circuit, the voltage with the firstpulsating waveform, and converting, by a transformer, the modulatedvoltage with the first pulsating waveform into voltage with a secondpulsating waveform; rectifying the voltage with the second pulsatingwaveform to output voltage with a third pulsating waveform, and applyingthe voltage with the third pulsating waveform to a battery of theterminal through the second charging interface; sampling currentcorresponding to the voltage with the third pulsating waveform to obtaina current sampling value, wherein the first current sampling circuit isselectively operable in a first current sampling mode and a secondcurrent sampling mode; and controlling the first current samplingcircuit to operate in the first current sampling mode or the secondcurrent sampling mode according to a charging triode, and regulating aduty cycle of the control signal according to the current sampling valueso that the voltage with the third pulsating waveform satisfies arequirement of charging.
 52. The charging method as claimed in claim 51,further comprising: regulating a frequency of the control signalaccording to the current sampling value.
 53. The charging method asclaimed in claim 51, further comprising: determining the charging modeby a communication between the first charging interface and theterminal, the charging mode comprising a first charging mode and asecond charging mode.
 54. The charging method as claimed in claim 53,further comprising: controlling the first current sampling circuit tooperate in the first current sampling mode, when a bidirectionalcommunication between the terminal and the power adapter via. the firstcharging interface is established to determine that the terminal ischarged by the first charging mode; and controlling the first currentsampling circuit to operate in the second current sampling mode, whenthe bidirectional communication between the terminal and the poweradapter via the first charging interface is established to determinethat the terminal is charged by the second charging mode.
 55. Thecharging method as claimed in claim 53, further comprising: when thebidirectional communication between the terminal and the power adaptervia the first charging interface is established to determine that theterminal is charged by the first charging mode, sending, by the poweradapter, a first instruction to the terminal, the first instructionconfigured to inquire of the terminal whether to enable the firstcharging mode or not; receiving, by the power adapter, a replyinstruction responsive to the first instruction from the terminal, thereply instruction responsive to the first instruction configured toindicate that the terminal agrees to enable the first charging mode. 56.The charging method as claimed in claim 55, wherein before sending thefirst instruction to the terminal, the power adapter charges theterminal through the second charging mode, and the charging methodcomprises: sending, by the power adapter, the first instruction to theterminal if a charging time of the second charging mode is longer than apredetermined threshold value.
 57. The charging method as claimed inclaim 55, further comprising: determining a charging voltagecorresponding to the first charging mode through the bidirectionalcommunication between the terminal and the power adapter via the firstcharging interface, and controlling the power adapter to adjust acharging voltage to the charging voltage corresponding to the firstcharging mode; and adjusting a charging current of the power adapter toa charging current corresponding to the first charging mode bycontrolling a switch circuit, and charging the terminal by the chargingcurrent corresponding to the first charging mode outputted by the poweradapter. 58-60. (canceled)
 61. The charging method as claimed in claim55, wherein during the process that the power adapter is operable in thefirst charging mode to charge the terminal, the charging method furthercomprises: continuously adjusting, by controlling the switch circuit,the charging current output to the battery from the power adapterthrough the bidirectional communication between the terminal and thepower adapter via the first charging interface. 62-66. (canceled) 67.The charging method as claimed in claim 53, wherein the terminalsupports the second charging mode and the first charging mode, and acharging current of the first charging mode is greater than a chargingcurrent of the second charging mode, wherein the charging method furthercomprises: determining, by the power adapter, that the first chargingmode is used to charge the terminal, through the bidirectionalcommunication between the second charging interface of the terminal andthe adapter; outputting, by the power adapter, the charging currentcorresponding to the first charging mode to charge the battery in theterminal.
 68. The charging method as claimed in claim 67, whereindetermining that the first charging mode is used to charge the terminal,through the bidirectional communication between the second charginginterface of the terminal and the adapter, comprises: receiving, by theterminal, a first instruction sent from the power adapter, the firstinstruction configured to inquire of the terminal whether to enable thefirst charging mode or not; sending, by the terminal, a replyinstruction responsive to the first instruction to the power adapter,the reply instruction responsive to the first instruction configured toindicate that the terminal agrees to enable the first charging mode.69-78. (canceled)